feat: add miner detail view

backend/app/locations/repository.py

@@ -229,3 +229,29 @@ class LocationMapRepository:
                     """
                 )
                 return dict(cur.fetchone())
+
+    def get_miner_location(self, miner_id: UUID) -> dict[str, Any] | None:
+        """Return the one current physical position assigned to a miner."""
+        with self._connection_scope() as connection:
+            with connection.cursor(row_factory=dict_row) as cur:
+                cur.execute(
+                    """
+                    SELECT sites.id AS site_id, sites.name AS site_name,
+                        rooms.id AS room_id,
+                        COALESCE(rooms.name, position.room_name) AS room_name,
+                        position.id AS position_id,
+                        position.rack_name AS rack_label,
+                        position.shelf_name AS shelf_label,
+                        position.position_label,
+                        position.position_index
+                    FROM location_positions AS position
+                    LEFT JOIN rooms ON rooms.id = position.room_id
+                    LEFT JOIN sites ON sites.id = rooms.site_id
+                    WHERE position.miner_id = %s
+                    ORDER BY position.id
+                    LIMIT 1
+                    """,
+                    (miner_id,),
+                )
+                row = cur.fetchone()
+                return dict(row) if row else None