Add non-blocking mode support to Telegram notification service

- Add `wait_for_response` parameter (default: true) for fire-and-forget operation
- Change supports_response to OPTIONAL to allow both modes
- Refactor execution logic into `_execute_telegram_notification` method
- Background tasks created with `hass.async_create_task` when wait_for_response=false
- Update documentation with non-blocking mode example and response behavior

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

custom_components/immich_album_watcher/translations/en.json

@@ -182,6 +182,10 @@
                 "chunk_delay": {
                     "name": "Chunk Delay",
                     "description": "Delay in milliseconds between sending multiple media groups (0-60000). Useful for rate limiting."
+                },
+                "wait_for_response": {
+                    "name": "Wait For Response",
+                    "description": "Wait for Telegram to finish processing before returning. Set to false for fire-and-forget (automation continues immediately)."
                 }
             }
         }