Add offline RefreshPrices, fix sync bugs, implement auto-restart

- Implement RefreshPrices for local-first mode
  - Update prices from local_components.current_price cache
  - Graceful degradation when component not found
  - Add PriceUpdatedAt timestamp to LocalConfiguration model
  - Support both authenticated and no-auth price refresh

- Fix sync duplicate entry bug
  - pushConfigurationUpdate now ensures server_id exists before update
  - Fetch from LocalConfiguration.ServerID or search on server if missing
  - Update local config with server_id after finding

- Add application auto-restart after settings save
  - Implement restartProcess() using syscall.Exec
  - Setup handler signals restart via channel
  - Setup page polls /health endpoint and redirects when ready
  - Add "Back" button on setup page when settings exist

- Fix setup handler password handling
  - Use PasswordEncrypted field consistently
  - Support empty password by using saved value

- Improve sync status handling
  - Add fallback for is_offline check in SyncStatusPartial
  - Enhance background sync logging with prefixes

- Update CLAUDE.md documentation
  - Mark Phase 2.5 tasks as complete
  - Add UI Improvements section with future tasks
  - Update SQLite tables documentation

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

web/templates/base.html

@@ -28,10 +28,10 @@
                 <div class="flex items-center space-x-4">
                     <!-- Sync Status Indicator (htmx-powered) -->
                     <div id="sync-status"
+                         class="flex items-center gap-3 text-sm"
                          hx-get="/partials/sync-status"
                          hx-trigger="load, refresh from:body, every 30s"
                          hx-swap="innerHTML">
-                        <span class="animate-pulse text-gray-400 text-xs">Загрузка...</span>
                     </div>
                     <span id="db-user" class="text-sm text-gray-600"></span>
                 </div>