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

templates/index.html

@@ -35,7 +35,7 @@
                 Rechercher
             </button>
         </form>
-        <div id="search-loading" class="htmx-indicator" style="margin-top: 15px; color: var(--primary); display: none;">
+        <div id="search-loading" class="htmx-indicator" style="margin-top: 15px; color: var(--primary);">
             <div class="spinner"></div> Recherche en cours...
         </div>
         <div style="margin-top: 15px; padding: 12px; background: rgba(0, 217, 255, 0.05); border: 1px solid rgba(0, 217, 255, 0.1); border-radius: var(--input-radius); font-size: 13px; color: var(--text-dim);">
@@ -92,7 +92,7 @@
                 Rechercher
             </button>
         </form>
-        <div id="series-search-loading" class="htmx-indicator" style="margin-top: 15px; color: var(--secondary); display: none;">
+        <div id="series-search-loading" class="htmx-indicator" style="margin-top: 15px; color: var(--secondary);">
             <div class="spinner"></div> Recherche en cours...
         </div>
         <div style="margin-top: 15px; padding: 12px; background: rgba(255, 107, 107, 0.05); border: 1px solid rgba(255, 107, 107, 0.1); border-radius: var(--input-radius); font-size: 13px; color: var(--text-dim);">