feat: integrate NFO repair into scheduled folder scan

- Add FolderScanService.run_folder_scan() calling perform_nfo_repair_scan()
- Remove startup-time NFO repair from fastapi_app lifespan
- Update docs/NFO_GUIDE.md: repair now runs as part of daily scan
- Update tests to verify integration wiring
- Update ARCHITECTURE.md and scheduler_service for scan scheduling

docs/ARCHITECTURE.md

@@ -81,6 +81,7 @@ src/server/
 |   +-- websocket_service.py# WebSocket broadcasting
 |   +-- queue_repository.py # Database persistence
 |   +-- nfo_service.py      # NFO metadata management
+|   +-- folder_scan_service.py # Daily folder maintenance scan
 +-- models/                 # Pydantic models
 |   +-- auth.py             # Auth request/response models
 |   +-- config.py           # Configuration models

docs/NFO_GUIDE.md

@@ -675,21 +675,25 @@ The XML serialisation lives in `src/core/utils/nfo_generator.py`
 
 ## 11. Automatic NFO Repair
 
-Every time the server starts, Aniworld scans all existing `tvshow.nfo` files and
-automatically repairs any that are missing required tags.
+NFO repair now runs as part of the scheduled daily folder scan rather than on every
+startup.  When the scheduler triggers `FolderScanService.run_folder_scan()`, the first
+step is `perform_nfo_repair_scan(background_loader=None)`.  Each incomplete NFO is
+queued as a background `asyncio` task, so the scan returns quickly while repairs
+continue asynchronously.
 
 ### How It Works
 
 1. **Scan** — `perform_nfo_repair_scan()` in
-   `src/server/services/initialization_service.py` is called from the FastAPI
-   lifespan after `perform_media_scan_if_needed()`.
+   `src/server/services/initialization_service.py` is called from
+   `FolderScanService.run_folder_scan()` (`src/server/services/folder_scan_service.py`).
 2. **Detect** — `nfo_needs_repair(nfo_path)` from
    `src/core/services/nfo_repair_service.py` parses each `tvshow.nfo` with
    `lxml` and checks for the 13 required tags listed below.
 3. **Repair** — Series whose NFO is incomplete are queued for background reload
-   via `BackgroundLoaderService.add_series_loading_task()`. The background
-   loader re-fetches metadata from TMDB and rewrites the NFO with all tags
-   populated.
+   via `asyncio.create_task`. Each task creates its own isolated
+   :class:`NFOService` / :class:`TMDBClient` so concurrent tasks never share an
+   ``aiohttp`` session — this prevents "Connector is closed" errors when many repairs
+   run in parallel.  A semaphore caps TMDB concurrency at 3 to stay within rate limits.
 
 ### Tags Checked (13 required)
 
@@ -734,8 +738,8 @@ This calls `NFOService.update_tvshow_nfo()` directly and overwrites the existing
 | File                                            | Purpose                                                                                        |
 | ----------------------------------------------- | ---------------------------------------------------------------------------------------------- |
 | `src/core/services/nfo_repair_service.py`       | `REQUIRED_TAGS`, `parse_nfo_tags`, `find_missing_tags`, `nfo_needs_repair`, `NfoRepairService` |
-| `src/server/services/initialization_service.py` | `perform_nfo_repair_scan` startup hook                                                         |
-| `src/server/fastapi_app.py`                     | Wires `perform_nfo_repair_scan` into the lifespan                                              |
+| `src/server/services/initialization_service.py` | `perform_nfo_repair_scan` — invoked from `FolderScanService`                                   |
+| `src/server/services/folder_scan_service.py`    | Calls `perform_nfo_repair_scan` during the scheduled daily folder scan                         |
 
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