refactor: migrate main.py to modular routers and add project roadmap

- Migrated monolithic main.py to feature-scoped routers in app/routers/
- Added GEMINI.md for project context and AI instructional guidelines
- Updated README.md with a comprehensive modernization plan (SQL migration, robust scraping DSL, frontend modernization)
- Improved authentication with cookie support and modular JS
- Updated test suite and documentation

app/routers/router_favorites.py

@@ -0,0 +1,119 @@
+"""
+Favorites management routes for Ohm Stream Downloader API.
+"""
+
+from fastapi import APIRouter, HTTPException
+from fastapi.requests import Request
+
+from app.favorites import get_favorites_manager
+
+router = APIRouter(prefix="/api/favorites", tags=["favorites"])
+
+
+@router.get("")
+async def list_favorites(
+    sort_by: str = "created_at",
+    order: str = "desc",
+    filter_provider: str = None,
+    filter_genre: str = None,
+):
+    """List all favorite anime with optional sorting and filtering"""
+    fav_manager = get_favorites_manager()
+    favorites = await fav_manager.list_favorites(
+        sort_by=sort_by,
+        order=order,
+        filter_provider=filter_provider,
+        filter_genre=filter_genre,
+    )
+    return {
+        "favorites": favorites,
+        "total": len(favorites),
+        "filters": {
+            "sort_by": sort_by,
+            "order": order,
+            "provider": filter_provider,
+            "genre": filter_genre,
+        },
+    }
+
+
+@router.post("")
+async def add_favorite(request: Request):
+    """Add an anime to favorites"""
+    data = await request.json()
+
+    required_fields = ["anime_id", "title", "url", "provider"]
+    for field in required_fields:
+        if field not in data:
+            raise HTTPException(
+                status_code=400, detail=f"Missing required field: {field}"
+            )
+
+    fav_manager = get_favorites_manager()
+    favorite = await fav_manager.add_favorite(
+        anime_id=data["anime_id"],
+        title=data["title"],
+        url=data["url"],
+        provider=data["provider"],
+        metadata=data.get("metadata"),
+        poster_url=data.get("poster_url"),
+    )
+
+    return {"status": "added", "favorite": favorite}
+
+
+@router.delete("/{anime_id}")
+async def remove_favorite(anime_id: str):
+    """Remove an anime from favorites"""
+    fav_manager = get_favorites_manager()
+    removed = await fav_manager.remove_favorite(anime_id)
+
+    if not removed:
+        raise HTTPException(status_code=404, detail="Favorite not found")
+
+    return {"status": "removed", "anime_id": anime_id}
+
+
+@router.get("/stats")
+async def get_favorites_stats():
+    """Get statistics about favorites"""
+    fav_manager = get_favorites_manager()
+    stats = await fav_manager.get_stats()
+    return stats
+
+
+@router.get("/{anime_id}")
+async def get_favorite(anime_id: str):
+    """Get details of a specific favorite anime"""
+    fav_manager = get_favorites_manager()
+    favorite = await fav_manager.get_favorite(anime_id)
+
+    if not favorite:
+        raise HTTPException(status_code=404, detail="Favorite not found")
+
+    return {"favorite": favorite}
+
+
+@router.post("/toggle")
+async def toggle_favorite(request: Request):
+    """Toggle an anime in favorites"""
+    data = await request.json()
+
+    required_fields = ["anime_id", "title", "url", "provider"]
+    for field in required_fields:
+        if field not in data:
+            raise HTTPException(
+                status_code=400, detail=f"Missing required field: {field}"
+            )
+
+    fav_manager = get_favorites_manager()
+    result = await fav_manager.toggle_favorite(
+        anime_id=data["anime_id"],
+        title=data["title"],
+        url=data["url"],
+        provider=data["provider"],
+        metadata=data.get("metadata"),
+        poster_url=data.get("poster_url"),
+    )
+
+    return result