fix: preserve Windows agent tasks during upgrades

agents/windows/README.md

@@ -51,15 +51,24 @@ Deploy Agent compatibility before enabling Hub enforcement of the
    reports the expected non-secret `VERSION`.
 5. Enable the matching Agent ID and shared secret on the Hub.
 
-The installer copies runtime code to `C:\MinerOpsAgent`, preserves
-`agent-config.json`, `agent-state.json`, and `logs\`, and registers or
-updates `MinerOpsAgent`, `MinerOpsAgentTray`,
-`MinerOpsApi3Enrichment`, and `MinerOpsPoolPoller`.
+The installer copies only managed runtime code to `C:\MinerOpsAgent` and
+preserves `agent-config.json`, `agent-state.json`, `logs\`, backups, probe
+output, and other runtime data. During an upgrade, existing definitions for
+`MinerOpsAgent`, `MinerOpsAgentTray`, `MinerOpsApi3Enrichment`, and
+`MinerOpsPoolPoller` are authoritative and are not rewritten. Missing tasks are
+created for a fresh or incomplete installation without hard-coded user names.
+
+If `MinerOpsAgent` was running before an upgrade, the installer stops only that
+Scheduled Task, waits for it to stop, replaces the managed files, and starts it
+again. A previously stopped Agent remains stopped. The tray and periodic tasks
+are not unnecessarily restarted.
 
 Before replacing existing runtime files, the installer copies them to a
-timestamped folder under `C:\MinerOpsAgent\backups`. To roll back, stop the
-Agent tasks, copy the selected backup's runtime files back into
-`C:\MinerOpsAgent`, and restart the tasks. `uninstall.ps1` unregisters the
-four tasks and removes runtime code while preserving local configuration,
+timestamped folder under `C:\MinerOpsAgent\backups`. A failed deployment
+automatically restores those managed files, removes tasks created by that
+failed attempt, and restores the main Agent's prior running state. For a manual
+rollback, stop `MinerOpsAgent`, restore the selected backup's runtime files,
+and restart it only if it was previously running. `uninstall.ps1` unregisters
+the four tasks and removes runtime code while preserving local configuration,
 state, logs, and backups.