feat: fix auth, provider health checks, search, and redesign UI

- Fix register/login: dict-style access on UserTable ORM objects
- Fix HTMX auth: inject JWT token in all HTMX request headers
- Fix FS7 search: use DLE AJAX endpoint /engine/ajax/search.php
- Fix ZT search: use ?p=series&search=QUERY (not DLE format)
- Fix provider health: load hardcoded providers + domain manager
- Add self.id to all anime/series providers
- Redesign homepage: Netflix-style horizontal scroll cards (.hc)
- Redesign search results: grouped by title, poster + synopsis + 3 buttons
- Add Télécharger dropdown: season download + episode picker
- Fix navbar CSS: restore .tabs flex layout, remove orphan rules
- Fix HTMX spinner: remove inline display:none, use CSS indicator
- Add AGENTS.md files across project for developer documentation

app/models/AGENTS.md

@@ -0,0 +1,45 @@
+# Models (app/models/)
+
+## OVERVIEW
+SQLModel/Pydantic models combining database tables (SQLModel) and API schemas (Pydantic). Each domain has a Base → Table → Schema pattern.
+
+## STRUCTURE
+```
+models/
+├── __init__.py        # Core: DownloadStatus, DownloadTask, DownloadRequest, AnimeMetadata, AnimeSearchResult
+├── auth.py            # User, UserCreate, UserLogin, Token, UserTable, UserInDB
+├── watchlist.py       # WatchlistItem, WatchlistSettings, AutoDownloadResult (+ Table variants)
+├── sonarr.py          # SonarrWebhookPayload, SonarrMapping, SonarrConfig, SonarrSeries (+ Table variants)
+├── favorites.py       # Favorites-related models
+└── settings.py        # AppSettings, AppSettingsUpdate (+ Table variant)
+```
+
+## WHERE TO LOOK
+
+| Need | File | Key Classes |
+|------|------|-------------|
+| Download task | `__init__.py` | `DownloadTask`, `DownloadStatus`, `DownloadRequest` |
+| Anime metadata | `__init__.py` | `AnimeMetadata`, `AnimeSearchResult` |
+| User/auth | `auth.py` | `User`, `UserCreate`, `UserLogin`, `Token`, `UserTable` |
+| Watchlist | `watchlist.py` | `WatchlistItem`, `WatchlistSettings`, `WatchlistItemTable` |
+| Sonarr | `sonarr.py` | `SonarrWebhookPayload`, `SonarrMapping`, `SonarrConfig`, `SonarrSeries` |
+| App settings | `settings.py` | `AppSettings`, `AppSettingsUpdate` |
+
+## CONVENTIONS
+
+**Triple-class pattern** (for DB-backed models):
+1. `*Base` — Pydantic base with shared fields
+2. `*Table` — SQLModel table class (`__tablename__`, `id`, FK columns)
+3. Final class — API schema (inherits from both, adds Config)
+
+**Enums**: PascalCase class, UPPER_SNAKE values (e.g., `DownloadStatus.PENDING`, `WatchlistStatus.ACTIVE`).
+
+**JSON columns**: Stored as JSON strings in SQLite, accessed via `@property` methods (e.g., `WatchlistItemTable.genres` parses `genres_json`).
+
+**Config classes**: Each API schema has `class Config: from_attributes = True` for ORM mode.
+
+## ANTI-PATTERNS
+
+- Do NOT add new fields to `*Base` without updating corresponding `*Table` and schema classes
+- Do NOT use `Optional` for required API fields — use Pydantic defaults
+- Empty `except:` in `settings.py:22` — known tech debt