fix: wire Phase 25.5a deploy docs and sync connectivity

- use app_network status for device sync connectivity checks
- mount migrate_phase25_5a.sql in server docker compose
- document manual server upgrade migration steps
- record verified Pi and unraid SSH access details in PLAN

Co-authored-by: Copilot <[email protected]>

server/README.md

@@ -66,6 +66,22 @@ so a permissive origin can't be used to steal a logged-in session.
    curl http://localhost:8098/health
    ```
 
+### Upgrading an existing unraid deployment
+
+If the Postgres volume already exists, mounted migration files do **not** run
+again automatically. After pulling new code, apply the new migrations manually:
+
+```bash
+cd /mnt/user/app/git/yaris-obd/server
+docker compose exec db psql -U yarisobd -d yarisobd -f /docker-entrypoint-initdb.d/migrate_phase24.sql
+docker compose exec db psql -U yarisobd -d yarisobd -f /docker-entrypoint-initdb.d/migrate_phase25_5a.sql
+docker compose up -d --build
+```
+
+Phase 25.5a adds the device identity sync columns (`owner_name`, `car_model`,
+`device_name`, `avatar_path`, `config_version`, `config_updated_at`) used by the
+Pi/server config sync flow.
+
 ## Registering a device and getting an API key
 
 Run this once per device (e.g. once for the Pi) after the stack is up: