diff --git a/backend/app/frontend/views.py b/backend/app/frontend/views.py
index 6eaab9b..2024473 100644
--- a/backend/app/frontend/views.py
+++ b/backend/app/frontend/views.py
@@ -142,6 +142,9 @@ def _map_content(can_manage_locations: bool = False) -> str:
 <section class="mine-map-workspace" id="mapWorkspace" hidden>
     <div class="map-main-column">
         <div id="mapLegend" class="map-legend" aria-label="Map legend"></div>
+        <p id="mapPermissionNote" class="map-notice" hidden>
+            Miner details require inventory access. Layout and occupancy remain visible.
+        </p>
         <div id="mapNotice" class="map-notice" role="status" hidden></div>
         <div id="mapViewport" class="map-viewport-v1"
             aria-label="Room racks, shelves, and positions"></div>
diff --git a/backend/tests/test_frontend_shell.py b/backend/tests/test_frontend_shell.py
index 3cad337..d9e2e42 100644
--- a/backend/tests/test_frontend_shell.py
+++ b/backend/tests/test_frontend_shell.py
@@ -1,3 +1,4 @@
+import re
 import unittest
 from pathlib import Path
 from unittest.mock import patch
@@ -157,6 +158,31 @@ class FrontendShellTests(unittest.TestCase):
             self.assertIn(value, response.text)
         self.assertNotIn("Live layout and telemetry data are not", response.text)
 
+    def test_map_script_dom_contract_matches_rendered_page(self):
+        self.authenticate()
+        response = self.client.get("/monitoring/map")
+        javascript = (STATIC_ROOT / "mine-map.js").read_text(encoding="utf-8")
+        declared_ids = re.search(
+            r"const ids = \[(.*?)\];",
+            javascript,
+            re.DOTALL,
+        )
+        self.assertIsNotNone(declared_ids)
+        required = set(
+            re.findall(
+                r'"([A-Za-z][A-Za-z0-9]+)"',
+                declared_ids.group(1),
+            )
+        )
+        required.update(
+            re.findall(
+                r'document\.getElementById\("([^"]+)"\)',
+                javascript,
+            )
+        )
+        rendered = set(re.findall(r'\bid="([^"]+)"', response.text))
+        self.assertEqual(required - rendered, set())
+
     def test_data_views_include_all_request_states(self):
         self.authenticate()
         for path in ("/operations/repairs", "/assets/miners"):
diff --git a/scripts/seed-development-demo.sh b/scripts/seed-development-demo.sh
new file mode 100755
index 0000000..c0f1e1a
--- /dev/null
+++ b/scripts/seed-development-demo.sh
@@ -0,0 +1,107 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+repo_root="$(cd "$(dirname "${BASH_SOURCE[0]}")/.." && pwd)"
+cd "${repo_root}"
+
+env_file="${MINEROPS_DEMO_ENV_FILE:-.env.dev}"
+project_name="${MINEROPS_DEMO_PROJECT:-minerops-dev}"
+mode="${1:-seed}"
+
+usage() {
+    cat <<'EOF'
+Usage: scripts/seed-development-demo.sh [--reseed]
+
+Seeds the current Docker development database with deterministic synthetic data.
+--reseed reapplies the mutable demo projections without deleting immutable history.
+EOF
+}
+
+case "${mode}" in
+    seed) [[ $# -eq 0 ]] || { usage >&2; exit 2; } ;;
+    --reseed) [[ $# -eq 1 ]] || { usage >&2; exit 2; } ;;
+    -h|--help) usage; exit 0 ;;
+    *) usage >&2; exit 2 ;;
+esac
+
+[[ -f "${env_file}" ]] || { echo "Missing development environment file: ${env_file}" >&2; exit 1; }
+[[ -f compose.dev.yaml ]] || { echo "Missing compose.dev.yaml." >&2; exit 1; }
+[[ -f sql/development-demo.sql ]] || { echo "Missing sql/development-demo.sql." >&2; exit 1; }
+
+env_value() {
+    awk -F= -v wanted="$1" '
+        $1 == wanted {
+            sub(/^[^=]*=/, "")
+            gsub(/\r$/, "")
+            print
+            exit
+        }
+    ' "${env_file}"
+}
+
+app_env="$(env_value APP_ENV)"
+database_name="$(env_value POSTGRES_DB)"
+database_host="$(env_value POSTGRES_HOST)"
+
+if [[ "${app_env}" != "development" ]]; then
+    echo "Refusing demo seed: APP_ENV must be exactly development." >&2
+    exit 1
+fi
+if [[ ! "${database_name}" =~ (^|_)(dev|development|test)(_|$) ]]; then
+    echo "Refusing demo seed: POSTGRES_DB must be clearly named for development or testing." >&2
+    exit 1
+fi
+if [[ "${database_name,,}" =~ (prod|production|live) ]]; then
+    echo "Refusing demo seed: POSTGRES_DB resembles a production database." >&2
+    exit 1
+fi
+if [[ "${database_host}" != "postgres" ]]; then
+    echo "Refusing demo seed: POSTGRES_HOST must be the compose.dev.yaml postgres service." >&2
+    exit 1
+fi
+
+compose=(
+    docker compose
+    --project-name "${project_name}"
+    --env-file "${env_file}"
+    -f compose.dev.yaml
+)
+
+"${compose[@]}" config --quiet
+if ! "${compose[@]}" ps --status running --services | grep -qx postgres; then
+    echo "Development PostgreSQL is not running for project ${project_name}." >&2
+    echo "Start it with: docker compose --project-name ${project_name} --env-file ${env_file} -f compose.dev.yaml up -d" >&2
+    exit 1
+fi
+
+migration_head="$(
+    "${compose[@]}" exec -T postgres sh -ec \
+        'psql -v ON_ERROR_STOP=1 -At -U "$POSTGRES_USER" -d "$POSTGRES_DB" -c "SELECT version_num FROM alembic_version"'
+)"
+if [[ "${migration_head}" != "0014_repair_parts_tracking" ]]; then
+    echo "Refusing demo seed: database Alembic head is ${migration_head:-missing}, expected 0014_repair_parts_tracking." >&2
+    exit 1
+fi
+
+if [[ "${mode}" == "--reseed" ]]; then
+    echo "Reapplying deterministic demo projections; immutable repair and MAC history will not be rewritten."
+else
+    echo "Seeding deterministic MinerOps development demo data..."
+fi
+
+"${compose[@]}" exec -T postgres sh -ec \
+    'psql -v ON_ERROR_STOP=1 -v app_env=development -U "$POSTGRES_USER" -d "$POSTGRES_DB"' \
+    < sql/development-demo.sql
+
+"${compose[@]}" exec -T postgres sh -ec \
+    'psql -v ON_ERROR_STOP=1 -At -F " | " -U "$POSTGRES_USER" -d "$POSTGRES_DB"' <<'SQL'
+SELECT
+    'demo summary',
+    count(*) FILTER (WHERE asset_tag LIKE 'DEMO-MIN-%') || ' miners',
+    (SELECT count(*) FROM location_positions WHERE source_file = 'MinerOps demo seed') || ' positions',
+    (SELECT count(*) FROM location_positions WHERE source_file = 'MinerOps demo seed' AND miner_id IS NULL) || ' empty',
+    (SELECT count(*) FROM repairs WHERE id::text LIKE 'd4000000-0000-4000-8000-%') || ' repairs'
+FROM miners;
+SQL
+
+echo "Demo data is ready at the configured development gateway."
diff --git a/scripts/test-development-demo.sh b/scripts/test-development-demo.sh
new file mode 100755
index 0000000..19da9fb
--- /dev/null
+++ b/scripts/test-development-demo.sh
@@ -0,0 +1,173 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+repo_root="$(cd "$(dirname "${BASH_SOURCE[0]}")/.." && pwd)"
+cd "${repo_root}"
+
+project_name="${MINEROPS_DEMO_TEST_PROJECT:-minerops-demo-test-$$}"
+dev_port="${MINEROPS_DEMO_TEST_PORT:-$((21000 + ($$ % 10000)))}"
+base_url="http://127.0.0.1:${dev_port}"
+tmp_prefix="/tmp/${project_name}"
+admin_cookie="${tmp_prefix}-admin.cookies"
+compose=(
+    docker compose
+    --project-name "${project_name}"
+    --env-file .env.dev
+    -f compose.dev.yaml
+)
+
+cleanup() {
+    status=$?
+    if (( status != 0 )); then
+        echo
+        echo "Development demo test failed. Recent service logs:"
+        "${compose[@]}" logs --no-color --tail 160 || true
+    fi
+    rm -f "${tmp_prefix}"-*
+    "${compose[@]}" down --volumes --remove-orphans >/dev/null 2>&1 || true
+    exit "${status}"
+}
+trap cleanup EXIT
+
+status_for() {
+    local path="$1"
+    curl --silent --output /dev/null --write-out '%{http_code}' \
+        -b "${admin_cookie}" -c "${admin_cookie}" "${base_url}${path}"
+}
+
+printf '%s\n' 'APP_ENV=production' > "${tmp_prefix}-production.env"
+if MINEROPS_DEMO_ENV_FILE="${tmp_prefix}-production.env" \
+    ./scripts/seed-development-demo.sh >"${tmp_prefix}-safety.out" 2>&1; then
+    echo "Demo seed accepted a production environment." >&2
+    exit 1
+fi
+grep -q 'APP_ENV must be exactly development' "${tmp_prefix}-safety.out"
+
+
+echo "Starting disposable MinerOps data services..."
+MINEROPS_DEV_PORT="${dev_port}" "${compose[@]}" up --detach postgres redis
+for attempt in $(seq 1 180); do
+    postgres_ready=false
+    redis_ready=false
+    if "${compose[@]}" exec -T postgres sh -ec \
+        'psql -U "$POSTGRES_USER" -d "$POSTGRES_DB" -Atqc "SELECT 1"' \
+        2>/dev/null | grep -qx 1; then
+        postgres_ready=true
+    fi
+    if "${compose[@]}" exec -T redis redis-cli ping 2>/dev/null | grep -qx PONG; then
+        redis_ready=true
+    fi
+    if [[ "${postgres_ready}" == "true" && "${redis_ready}" == "true" ]]; then
+        break
+    fi
+    (( attempt < 180 )) || { echo "Disposable data services did not become ready." >&2; exit 1; }
+    sleep 1
+done
+
+echo "Building and starting the disposable backend..."
+MINEROPS_DEV_PORT="${dev_port}" "${compose[@]}" up --detach --build --no-deps backend
+backend_container="$("${compose[@]}" ps -q backend)"
+for attempt in $(seq 1 180); do
+    backend_health="$(docker inspect --format '{{if .State.Health}}{{.State.Health.Status}}{{else}}{{.State.Status}}{{end}}' "${backend_container}")"
+    [[ "${backend_health}" == "healthy" ]] && break
+    [[ "${backend_health}" != "exited" && "${backend_health}" != "dead" ]] || { echo "Disposable backend exited." >&2; exit 1; }
+    (( attempt < 180 )) || { echo "Disposable backend did not become ready." >&2; exit 1; }
+    sleep 1
+done
+
+echo "Starting the disposable gateway..."
+MINEROPS_DEV_PORT="${dev_port}" "${compose[@]}" up --detach --no-deps gateway
+for attempt in $(seq 1 90); do
+    if curl --fail --silent "${base_url}/api/health" >"${tmp_prefix}-health.json"; then
+        break
+    fi
+    (( attempt < 90 )) || { echo "Disposable gateway did not become ready." >&2; exit 1; }
+    sleep 1
+done
+echo "Creating disposable development administrator..."
+curl --fail --silent -c "${admin_cookie}" \
+    -H 'Content-Type: application/json' \
+    --data '{"username":"admin","display_name":"Test Administrator","email":"admin@example.com","password":"MinerOpsTest!123"}' \
+    "${base_url}/api/auth/setup-admin" >"${tmp_prefix}-setup.json"
+grep -q '"role":"Admin"' "${tmp_prefix}-setup.json"
+
+echo "Seeding and reapplying the deterministic fixture..."
+MINEROPS_DEMO_PROJECT="${project_name}" ./scripts/seed-development-demo.sh
+MINEROPS_DEMO_PROJECT="${project_name}" ./scripts/seed-development-demo.sh
+MINEROPS_DEMO_PROJECT="${project_name}" ./scripts/seed-development-demo.sh --reseed
+
+counts="$(
+    "${compose[@]}" exec -T postgres sh -ec \
+        'psql -v ON_ERROR_STOP=1 -At -F "|" -U "$POSTGRES_USER" -d "$POSTGRES_DB"' <<'SQL'
+SELECT
+    count(*) FILTER (WHERE asset_tag LIKE 'DEMO-MIN-%'),
+    (SELECT count(*) FROM location_positions WHERE source_file = 'MinerOps demo seed'),
+    (SELECT count(*) FROM location_positions WHERE source_file = 'MinerOps demo seed' AND miner_id IS NULL),
+    (SELECT count(*) FROM repairs WHERE id::text LIKE 'd4000000-0000-4000-8000-%'),
+    (SELECT count(*) FROM repairs WHERE id::text LIKE 'd4000000-0000-4000-8000-%' AND status IN ('OPEN', 'IN_PROGRESS', 'WAITING_FOR_PARTS', 'READY_FOR_TEST')),
+    (SELECT count(*) FROM repair_events WHERE id::text LIKE 'd5000000-0000-4000-8000-%'),
+    (SELECT count(*) FROM miner_status_snapshots WHERE id::text LIKE 'd3000000-0000-4000-8000-%')
+FROM miners;
+SQL
+)"
+[[ "${counts}" == "30|50|23|4|3|8|23" ]]
+
+echo "Checking live authenticated pages and APIs..."
+for path in /dashboard /assets/miners /monitoring/map /operations/repairs; do
+    [[ "$(status_for "${path}")" == "200" ]]
+done
+curl --fail --silent -b "${admin_cookie}" "${base_url}/monitoring/map" >"${tmp_prefix}-map.html"
+curl --fail --silent -b "${admin_cookie}" "${base_url}/assets/minerops-mine-map.js" >"${tmp_prefix}-map.js"
+curl --fail --silent -b "${admin_cookie}" "${base_url}/api/location/map" >"${tmp_prefix}-map.json"
+curl --fail --silent -b "${admin_cookie}" "${base_url}/api/inventory/miners?limit=100" >"${tmp_prefix}-miners.json"
+curl --fail --silent -b "${admin_cookie}" "${base_url}/api/repairs/queue" >"${tmp_prefix}-repairs.json"
+
+for id in mapSite mapRoom mapLayer mapPermissionNote mapViewport mapInspector; do
+    grep -q "id=\"${id}\"" "${tmp_prefix}-map.html"
+done
+for layer in temperature hashrate power repair; do
+    grep -q "\"${layer}\"" "${tmp_prefix}-map.js"
+done
+! grep -q "Cannot set properties of null" "${tmp_prefix}-map.html"
+
+python3 - "${tmp_prefix}-map.json" "${tmp_prefix}-miners.json" "${tmp_prefix}-repairs.json" <<'PY'
+import json
+import sys
+
+with open(sys.argv[1], encoding="utf-8") as handle:
+    mine_map = json.load(handle)
+with open(sys.argv[2], encoding="utf-8") as handle:
+    miners = json.load(handle)
+with open(sys.argv[3], encoding="utf-8") as handle:
+    repairs = json.load(handle)
+
+assert mine_map["meta"]["miner_details_included"] is True
+assert mine_map["meta"]["position_count"] == 50
+assert len(mine_map["data"]["sites"]) >= 1
+assert {room["name"] for room in mine_map["data"]["rooms"]} >= {"Demo Unit A", "Demo Unit B"}
+positions = mine_map["data"]["positions"]
+assert {position["rack_name"] for position in positions} >= {"A1", "A2", "A3", "B1", "B2"}
+assert sum(position["occupied"] for position in positions) == 27
+assert sum(not position["occupied"] for position in positions) == 23
+assert any(position["active_repair"] for position in positions)
+assert any(position["occupied"] and position["observed_at"] is None for position in positions)
+assert any(position["hashrate_ths"] == 0 for position in positions)
+assert len({position["model"] for position in positions if position["model"]}) == 6
+assert len({position["chip_temp_max_c"] for position in positions if position["chip_temp_max_c"] is not None}) >= 5
+assert len(miners["data"]) == 30
+assert any(miner["asset_id"] == "DEMO-MIN-001" for miner in miners["data"])
+assert repairs["data"]["summary"]["total"] == 3
+assert {item["latest_event_status"] for item in repairs["data"]["items"]} == {"open", "waiting_parts", "testing"}
+PY
+
+for query in \
+    'query=DEMO-MIN-001' \
+    'query=DEMO-SERIAL-001' \
+    'query=02%3A00%3A00%3A00%3A00%3A01' \
+    'query=M60S'; do
+    response="$(curl --fail --silent -b "${admin_cookie}" "${base_url}/api/inventory/miners?${query}&limit=100")"
+    [[ "${response}" == *'"returned":'* ]]
+    [[ "${response}" != *'"returned":0'* ]]
+done
+
+echo "Development demo seed and live UI/API smoke checks passed."
diff --git a/sql/development-demo.sql b/sql/development-demo.sql
new file mode 100644
index 0000000..274de11
--- /dev/null
+++ b/sql/development-demo.sql
@@ -0,0 +1,501 @@
+\set ON_ERROR_STOP on
+
+BEGIN;
+SET CONSTRAINTS ALL DEFERRED;
+SELECT set_config('minerops.seed_environment', :'app_env', true);
+
+DO $$
+BEGIN
+    IF current_setting('minerops.seed_environment', true) <> 'development' THEN
+        RAISE EXCEPTION 'MinerOps demo seed is restricted to APP_ENV=development';
+    END IF;
+    IF current_database() !~* '(^|_)(dev|development|test)(_|$)' THEN
+        RAISE EXCEPTION 'MinerOps demo seed requires a development or test database name; got %', current_database();
+    END IF;
+END $$;
+
+CREATE TEMP TABLE demo_seed_context ON COMMIT DROP AS
+SELECT users.id AS actor_id
+FROM users
+JOIN roles ON roles.id = users.role_id
+WHERE users.is_active AND roles.name = 'Admin'
+ORDER BY users.created_at, users.id
+LIMIT 1;
+
+DO $$
+BEGIN
+    IF NOT EXISTS (SELECT 1 FROM demo_seed_context) THEN
+        RAISE EXCEPTION 'Create an active Admin account before seeding MinerOps demo data';
+    END IF;
+END $$;
+
+INSERT INTO sites (id, name, description)
+VALUES (
+    'd0000000-0000-4000-8000-000000000001',
+    'Demo Mining Site',
+    'Synthetic development-only MinerOps fixture. Never use as production data.'
+)
+ON CONFLICT (id) DO UPDATE SET
+    name = EXCLUDED.name,
+    description = EXCLUDED.description,
+    updated_at = now();
+
+INSERT INTO rooms (id, site_id, name, description, sort_order)
+VALUES
+    (
+        'd0000000-0000-4000-8000-000000000101',
+        'd0000000-0000-4000-8000-000000000001',
+        'Demo Unit A',
+        'Synthetic room with racks A1 through A3.',
+        10
+    ),
+    (
+        'd0000000-0000-4000-8000-000000000102',
+        'd0000000-0000-4000-8000-000000000001',
+        'Demo Unit B',
+        'Synthetic room with racks B1 and B2.',
+        20
+    )
+ON CONFLICT (id) DO UPDATE SET
+    site_id = EXCLUDED.site_id,
+    name = EXCLUDED.name,
+    description = EXCLUDED.description,
+    sort_order = EXCLUDED.sort_order,
+    updated_at = now();
+
+WITH demo_miners AS (
+    SELECT
+        i,
+        ('d1000000-0000-4000-8000-' || lpad(i::text, 12, '0'))::uuid AS id,
+        CASE
+            WHEN i <= 18 THEN 'd0000000-0000-4000-8000-000000000101'::uuid
+            WHEN i <= 27 THEN 'd0000000-0000-4000-8000-000000000102'::uuid
+            ELSE NULL
+        END AS room_id,
+        (ARRAY['M30S', 'M30S+', 'M50', 'M50S', 'M60', 'M60S'])[((i - 1) % 6) + 1] AS model,
+        format('02:00:00:00:00:%s', upper(lpad(to_hex(i), 2, '0'))) AS mac,
+        CASE
+            WHEN i IN (21, 22, 23) THEN 'in_repair'
+            WHEN i IN (25, 26, 29) THEN 'spare'
+            WHEN i = 28 THEN 'retired'
+            ELSE 'active'
+        END AS lifecycle_status,
+        CASE
+            WHEN i IN (6, 12, 21, 22, 23, 24) THEN 'offline'
+            WHEN i IN (5, 10, 20, 25, 28, 29, 30) THEN 'unknown'
+            ELSE 'online'
+        END AS runtime_status,
+        CASE
+            WHEN i IN (5, 10, 20, 25, 28, 29, 30) THEN NULL
+            WHEN i = 19 THEN now() - interval '3 days'
+            WHEN i IN (21, 22, 23) THEN now() - make_interval(hours => i - 17)
+            ELSE now() - make_interval(mins => i * 3)
+        END AS observed_at
+    FROM generate_series(1, 30) AS series(i)
+)
+INSERT INTO miners (
+    id, site_id, room_id, asset_tag, current_mac, current_ip, hostname,
+    miner_sn, power_sn, control_board_sn, model, miner_type, api_version,
+    firmware_version, platform, chip, status, lifecycle_status, notes,
+    first_seen_at, last_seen_at, created_at, updated_at
+)
+SELECT
+    id,
+    'd0000000-0000-4000-8000-000000000001',
+    room_id,
+    format('DEMO-MIN-%s', lpad(i::text, 3, '0')),
+    mac,
+    ('192.0.2.' || i)::inet,
+    format('demo-miner-%s', lpad(i::text, 3, '0')),
+    format('DEMO-SERIAL-%s', lpad(i::text, 3, '0')),
+    format('DEMO-PSU-%s', lpad(i::text, 3, '0')),
+    format('DEMO-CB-%s', lpad(i::text, 3, '0')),
+    model,
+    'WhatsMiner',
+    '3.2-demo',
+    format('DEMO-FW-2026.%s', ((i - 1) % 4) + 1),
+    'Demo Platform',
+    'Synthetic ASIC',
+    runtime_status,
+    lifecycle_status,
+    'Synthetic development-only miner. No real fleet identity or measurements.',
+    now() - make_interval(days => 120 - i),
+    observed_at,
+    now() - make_interval(days => 120 - i),
+    now()
+FROM demo_miners
+ON CONFLICT (id) DO UPDATE SET
+    site_id = EXCLUDED.site_id,
+    room_id = EXCLUDED.room_id,
+    asset_tag = EXCLUDED.asset_tag,
+    current_mac = EXCLUDED.current_mac,
+    current_ip = EXCLUDED.current_ip,
+    hostname = EXCLUDED.hostname,
+    miner_sn = EXCLUDED.miner_sn,
+    power_sn = EXCLUDED.power_sn,
+    control_board_sn = EXCLUDED.control_board_sn,
+    model = EXCLUDED.model,
+    miner_type = EXCLUDED.miner_type,
+    api_version = EXCLUDED.api_version,
+    firmware_version = EXCLUDED.firmware_version,
+    platform = EXCLUDED.platform,
+    chip = EXCLUDED.chip,
+    status = EXCLUDED.status,
+    lifecycle_status = EXCLUDED.lifecycle_status,
+    notes = EXCLUDED.notes,
+    first_seen_at = EXCLUDED.first_seen_at,
+    last_seen_at = EXCLUDED.last_seen_at,
+    updated_at = now();
+
+WITH room_a AS (
+    SELECT
+        n AS ordinal,
+        'd0000000-0000-4000-8000-000000000101'::uuid AS room_id,
+        'Demo Unit A'::text AS room_name,
+        format('A%s', ((n - 1) / 10) + 1) AS rack_name,
+        ((n - 1) % 10) / 5 + 1 AS shelf_index,
+        ((n - 1) % 5) + 1 AS position_index,
+        CASE WHEN n <= 18 THEN n ELSE NULL END AS miner_number
+    FROM generate_series(1, 30) AS positions(n)
+),
+room_b AS (
+    SELECT
+        n + 30 AS ordinal,
+        'd0000000-0000-4000-8000-000000000102'::uuid AS room_id,
+        'Demo Unit B'::text AS room_name,
+        format('B%s', ((n - 1) / 10) + 1) AS rack_name,
+        ((n - 1) % 10) / 5 + 1 AS shelf_index,
+        ((n - 1) % 5) + 1 AS position_index,
+        CASE WHEN n <= 9 THEN n + 18 ELSE NULL END AS miner_number
+    FROM generate_series(1, 20) AS positions(n)
+),
+positions AS (
+    SELECT * FROM room_a
+    UNION ALL
+    SELECT * FROM room_b
+)
+INSERT INTO location_positions (
+    id, room_id, room_name, rack_name, shelf_name, shelf_index,
+    position_index, position_label, position_kind, position_status,
+    expected_mac, miner_id, notes, source_file, source_sheet, created_at, updated_at
+)
+SELECT
+    ('d2000000-0000-4000-8000-' || lpad(ordinal::text, 12, '0'))::uuid,
+    room_id,
+    room_name,
+    rack_name,
+    format('Shelf %s', shelf_index),
+    shelf_index,
+    position_index,
+    format('%s-S%s-P%s', rack_name, shelf_index, position_index),
+    'miner_slot',
+    CASE WHEN miner_number IS NULL THEN 'available' ELSE 'occupied' END,
+    CASE WHEN ordinal = 50 THEN '02:00:00:00:00:FE' ELSE NULL END,
+    CASE WHEN miner_number IS NULL THEN NULL ELSE
+        ('d1000000-0000-4000-8000-' || lpad(miner_number::text, 12, '0'))::uuid
+    END,
+    'Synthetic development-only position.',
+    'MinerOps demo seed',
+    'Synthetic layout',
+    now(),
+    now()
+FROM positions
+ON CONFLICT (id) DO UPDATE SET
+    room_id = EXCLUDED.room_id,
+    room_name = EXCLUDED.room_name,
+    rack_name = EXCLUDED.rack_name,
+    shelf_name = EXCLUDED.shelf_name,
+    shelf_index = EXCLUDED.shelf_index,
+    position_index = EXCLUDED.position_index,
+    position_label = EXCLUDED.position_label,
+    position_kind = EXCLUDED.position_kind,
+    position_status = EXCLUDED.position_status,
+    expected_mac = EXCLUDED.expected_mac,
+    miner_id = EXCLUDED.miner_id,
+    notes = EXCLUDED.notes,
+    source_file = EXCLUDED.source_file,
+    source_sheet = EXCLUDED.source_sheet,
+    updated_at = now();
+
+WITH demo_miners AS (
+    SELECT
+        i,
+        ('d1000000-0000-4000-8000-' || lpad(i::text, 12, '0'))::uuid AS miner_id,
+        CASE
+            WHEN i <= 18 THEN i
+            WHEN i <= 27 THEN i + 12
+            ELSE NULL
+        END AS position_ordinal
+    FROM generate_series(1, 30) AS series(i)
+)
+INSERT INTO miner_location_states (
+    miner_id, asset_state, location_position_id, state_notes,
+    updated_by_user_id, updated_at
+)
+SELECT
+    miner_id,
+    CASE
+        WHEN i IN (21, 22, 23) THEN 'repair'
+        WHEN i IN (25, 26, 29) THEN 'storage'
+        WHEN i = 28 THEN 'decommissioned'
+        WHEN position_ordinal IS NULL THEN 'waiting_placement'
+        ELSE 'shelved'
+    END,
+    CASE WHEN position_ordinal IS NULL THEN NULL ELSE
+        ('d2000000-0000-4000-8000-' || lpad(position_ordinal::text, 12, '0'))::uuid
+    END,
+    'Synthetic development-only location state.',
+    (SELECT actor_id FROM demo_seed_context),
+    now()
+FROM demo_miners
+ON CONFLICT (miner_id) DO UPDATE SET
+    asset_state = EXCLUDED.asset_state,
+    location_position_id = EXCLUDED.location_position_id,
+    state_notes = EXCLUDED.state_notes,
+    updated_by_user_id = EXCLUDED.updated_by_user_id,
+    updated_at = now();
+
+WITH telemetry AS (
+    SELECT
+        i,
+        ('d1000000-0000-4000-8000-' || lpad(i::text, 12, '0'))::uuid AS miner_id,
+        CASE
+            WHEN i = 19 THEN now() - interval '3 days'
+            WHEN i IN (21, 22, 23) THEN now() - make_interval(hours => i - 17)
+            ELSE now() - make_interval(mins => i * 3)
+        END AS observed_at,
+        CASE ((i - 1) % 6)
+            WHEN 0 THEN 90
+            WHEN 1 THEN 100
+            WHEN 2 THEN 112
+            WHEN 3 THEN 126
+            WHEN 4 THEN 170
+            ELSE 186
+        END::numeric AS nominal_ths,
+        i IN (6, 12, 21, 22, 23, 24) AS stopped
+    FROM generate_series(1, 30) AS series(i)
+    WHERE i NOT IN (5, 10, 20, 25, 28, 29, 30)
+)
+INSERT INTO miner_status_snapshots (
+    id, miner_id, observed_ip, ip_address, mac_address, observed_at,
+    mhs_av, mhs_1m, mhs_15m, hs_rt, power_w, power_rate_w_per_th,
+    env_temp_c, chip_temp_min_c, chip_temp_max_c, chip_temp_avg_c,
+    fan_speed_in_rpm, fan_speed_out_rpm, uptime_seconds, elapsed_seconds,
+    hash_stable, pool_rejected_percent, raw_summary_json, created_at
+)
+SELECT
+    ('d3000000-0000-4000-8000-' || lpad(i::text, 12, '0'))::uuid,
+    miner_id,
+    ('192.0.2.' || i)::inet,
+    ('192.0.2.' || i)::inet,
+    format('02:00:00:00:00:%s', upper(lpad(to_hex(i), 2, '0'))),
+    observed_at,
+    CASE WHEN stopped THEN 0 ELSE (nominal_ths + ((i % 5) - 2) * 0.7) * 1000000 END,
+    CASE WHEN stopped THEN 0 ELSE (nominal_ths + ((i % 4) - 1) * 0.6) * 1000000 END,
+    CASE WHEN stopped THEN 0 ELSE (nominal_ths + ((i % 3) - 1) * 0.4) * 1000000 END,
+    CASE WHEN stopped THEN 0 ELSE (nominal_ths + ((i % 5) - 2) * 0.7) * 1000000 END,
+    CASE WHEN stopped THEN 0 ELSE 2920 + nominal_ths * 4.8 + (i % 7) * 23 END,
+    CASE WHEN stopped THEN NULL ELSE round((28 + (i % 5) * 0.6)::numeric, 2) END,
+    24 + (i % 7),
+    48 + (i % 6) * 2,
+    58 + (i % 9) * 3,
+    54 + (i % 8) * 2,
+    CASE WHEN stopped THEN 0 ELSE 4700 + (i % 6) * 120 END,
+    CASE WHEN stopped THEN 0 ELSE 4950 + (i % 5) * 135 END,
+    CASE WHEN stopped THEN 0 ELSE 86400 + i * 731 END,
+    CASE WHEN stopped THEN 0 ELSE 86400 + i * 731 END,
+    CASE WHEN stopped THEN false WHEN i IN (9, 17) THEN false ELSE true END,
+    CASE WHEN stopped THEN 0 ELSE round((0.15 + (i % 6) * 0.08)::numeric, 2) END,
+    jsonb_build_object(
+        'fixture', 'MinerOps development demo',
+        'synthetic', true,
+        'model_index', i
+    ),
+    observed_at
+FROM telemetry
+ON CONFLICT (id) DO UPDATE SET
+    observed_ip = EXCLUDED.observed_ip,
+    ip_address = EXCLUDED.ip_address,
+    mac_address = EXCLUDED.mac_address,
+    observed_at = EXCLUDED.observed_at,
+    mhs_av = EXCLUDED.mhs_av,
+    mhs_1m = EXCLUDED.mhs_1m,
+    mhs_15m = EXCLUDED.mhs_15m,
+    hs_rt = EXCLUDED.hs_rt,
+    power_w = EXCLUDED.power_w,
+    power_rate_w_per_th = EXCLUDED.power_rate_w_per_th,
+    env_temp_c = EXCLUDED.env_temp_c,
+    chip_temp_min_c = EXCLUDED.chip_temp_min_c,
+    chip_temp_max_c = EXCLUDED.chip_temp_max_c,
+    chip_temp_avg_c = EXCLUDED.chip_temp_avg_c,
+    fan_speed_in_rpm = EXCLUDED.fan_speed_in_rpm,
+    fan_speed_out_rpm = EXCLUDED.fan_speed_out_rpm,
+    uptime_seconds = EXCLUDED.uptime_seconds,
+    elapsed_seconds = EXCLUDED.elapsed_seconds,
+    hash_stable = EXCLUDED.hash_stable,
+    pool_rejected_percent = EXCLUDED.pool_rejected_percent,
+    raw_summary_json = EXCLUDED.raw_summary_json,
+    created_at = EXCLUDED.created_at;
+
+INSERT INTO repairs (
+    id, miner_id, status, reason, opened_at, opened_by,
+    completed_at, completed_by, completion_summary, resulting_lifecycle
+)
+VALUES
+    (
+        'd4000000-0000-4000-8000-000000000001',
+        'd1000000-0000-4000-8000-000000000021',
+        'OPEN', 'CONTROL_BOARD', now() - interval '2 days',
+        (SELECT actor_id FROM demo_seed_context),
+        NULL, NULL, NULL, NULL
+    ),
+    (
+        'd4000000-0000-4000-8000-000000000002',
+        'd1000000-0000-4000-8000-000000000022',
+        'WAITING_FOR_PARTS', 'PSU', now() - interval '5 days',
+        (SELECT actor_id FROM demo_seed_context),
+        NULL, NULL, NULL, NULL
+    ),
+    (
+        'd4000000-0000-4000-8000-000000000003',
+        'd1000000-0000-4000-8000-000000000023',
+        'READY_FOR_TEST', 'HASHBOARD', now() - interval '1 day',
+        (SELECT actor_id FROM demo_seed_context),
+        NULL, NULL, NULL, NULL
+    ),
+    (
+        'd4000000-0000-4000-8000-000000000004',
+        'd1000000-0000-4000-8000-000000000004',
+        'COMPLETED', 'PREVENTIVE_MAINTENANCE', now() - interval '21 days',
+        (SELECT actor_id FROM demo_seed_context),
+        now() - interval '20 days',
+        (SELECT actor_id FROM demo_seed_context),
+        'Synthetic scheduled inspection completed successfully.',
+        'active'
+    )
+ON CONFLICT (id) DO NOTHING;
+
+INSERT INTO repair_events (
+    id, repair_id, sequence, event_type, created_at, created_by, payload
+)
+VALUES
+    (
+        'd5000000-0000-4000-8000-000000000001',
+        'd4000000-0000-4000-8000-000000000001',
+        1, 'REPAIR_STARTED', now() - interval '2 days',
+        (SELECT actor_id FROM demo_seed_context),
+        jsonb_build_object('reason', 'CONTROL_BOARD', 'from_lifecycle', 'active', 'to_lifecycle', 'in_repair')
+    ),
+    (
+        'd5000000-0000-4000-8000-000000000002',
+        'd4000000-0000-4000-8000-000000000001',
+        2, 'INITIAL_NOTE', now() - interval '2 days' + interval '10 minutes',
+        (SELECT actor_id FROM demo_seed_context),
+        jsonb_build_object('note', 'Synthetic intermittent control-board communication fault.')
+    ),
+    (
+        'd5000000-0000-4000-8000-000000000003',
+        'd4000000-0000-4000-8000-000000000002',
+        1, 'REPAIR_STARTED', now() - interval '5 days',
+        (SELECT actor_id FROM demo_seed_context),
+        jsonb_build_object('reason', 'PSU', 'from_lifecycle', 'spare', 'to_lifecycle', 'in_repair')
+    ),
+    (
+        'd5000000-0000-4000-8000-000000000004',
+        'd4000000-0000-4000-8000-000000000002',
+        2, 'INITIAL_NOTE', now() - interval '5 days' + interval '15 minutes',
+        (SELECT actor_id FROM demo_seed_context),
+        jsonb_build_object('note', 'Synthetic replacement PSU is awaiting delivery.')
+    ),
+    (
+        'd5000000-0000-4000-8000-000000000005',
+        'd4000000-0000-4000-8000-000000000003',
+        1, 'REPAIR_STARTED', now() - interval '1 day',
+        (SELECT actor_id FROM demo_seed_context),
+        jsonb_build_object('reason', 'HASHBOARD', 'from_lifecycle', 'active', 'to_lifecycle', 'in_repair')
+    ),
+    (
+        'd5000000-0000-4000-8000-000000000006',
+        'd4000000-0000-4000-8000-000000000003',
+        2, 'INITIAL_NOTE', now() - interval '1 day' + interval '20 minutes',
+        (SELECT actor_id FROM demo_seed_context),
+        jsonb_build_object('note', 'Synthetic hashboard repair passed bench checks and is ready for test.')
+    ),
+    (
+        'd5000000-0000-4000-8000-000000000007',
+        'd4000000-0000-4000-8000-000000000004',
+        1, 'REPAIR_STARTED', now() - interval '21 days',
+        (SELECT actor_id FROM demo_seed_context),
+        jsonb_build_object('reason', 'PREVENTIVE_MAINTENANCE', 'from_lifecycle', 'active', 'to_lifecycle', 'in_repair')
+    ),
+    (
+        'd5000000-0000-4000-8000-000000000008',
+        'd4000000-0000-4000-8000-000000000004',
+        2, 'REPAIR_COMPLETED', now() - interval '20 days',
+        (SELECT actor_id FROM demo_seed_context),
+        jsonb_build_object(
+            'previous_miner_lifecycle', 'in_repair',
+            'resulting_miner_lifecycle', 'active',
+            'pre_repair_lifecycle', 'active',
+            'completion_summary', 'Synthetic scheduled inspection completed successfully.'
+        )
+    )
+ON CONFLICT (id) DO NOTHING;
+
+INSERT INTO miner_maintenance_events (
+    id, miner_id, event_type, event_status, event_title, description,
+    event_at, created_by_user_id, created_at, updated_at
+)
+VALUES
+    (
+        'd6000000-0000-4000-8000-000000000001',
+        'd1000000-0000-4000-8000-000000000021',
+        'repair', 'open', 'Control board diagnostics',
+        'Synthetic repair projection. Intermittent control-board communication fault.',
+        now() - interval '2 days', (SELECT actor_id FROM demo_seed_context), now(), now()
+    ),
+    (
+        'd6000000-0000-4000-8000-000000000002',
+        'd1000000-0000-4000-8000-000000000022',
+        'repair', 'waiting_parts', 'Awaiting replacement PSU',
+        'Synthetic repair projection. Replacement PSU is awaiting delivery.',
+        now() - interval '5 days', (SELECT actor_id FROM demo_seed_context), now(), now()
+    ),
+    (
+        'd6000000-0000-4000-8000-000000000003',
+        'd1000000-0000-4000-8000-000000000023',
+        'repair', 'testing', 'Hashboard validation',
+        'Synthetic repair projection. Repaired hashboard is ready for a controlled test.',
+        now() - interval '1 day', (SELECT actor_id FROM demo_seed_context), now(), now()
+    ),
+    (
+        'd6000000-0000-4000-8000-000000000004',
+        'd1000000-0000-4000-8000-000000000004',
+        'repair', 'completed', 'Scheduled inspection complete',
+        'Synthetic historical repair projection.',
+        now() - interval '20 days', (SELECT actor_id FROM demo_seed_context), now(), now()
+    )
+ON CONFLICT (id) DO UPDATE SET
+    event_status = EXCLUDED.event_status,
+    event_title = EXCLUDED.event_title,
+    description = EXCLUDED.description,
+    event_at = EXCLUDED.event_at,
+    created_by_user_id = EXCLUDED.created_by_user_id,
+    updated_at = now();
+
+DO $$
+DECLARE
+    miner_count integer;
+    position_count integer;
+    repair_count integer;
+BEGIN
+    SELECT count(*) INTO miner_count FROM miners WHERE asset_tag LIKE 'DEMO-MIN-%';
+    SELECT count(*) INTO position_count FROM location_positions WHERE source_file = 'MinerOps demo seed';
+    SELECT count(*) INTO repair_count FROM repairs WHERE id::text LIKE 'd4000000-0000-4000-8000-%';
+    IF miner_count <> 30 OR position_count <> 50 OR repair_count <> 4 THEN
+        RAISE EXCEPTION 'Demo seed verification failed: miners %, positions %, repairs %',
+            miner_count, position_count, repair_count;
+    END IF;
+END $$;
+
+COMMIT;