feat: enhance model caching and output modalities handling

- Updated `refresh_models_cache` to include output modalities in the models cache.
- Added `get_model_output_modalities` function to retrieve output modalities for a specific model.
- Modified tests to cover new functionality for output modalities.
- Updated OpenRouter video generation functions to support audio generation and improved error handling.
- Enhanced dashboard to display generated images and videos.
- Refactored frontend templates to accommodate new data structures for generated content.
- Adjusted tests to validate changes in model handling and dashboard rendering.

Co-authored-by: Copilot <copilot@github.com>

backend/app/main.py

@@ -1,10 +1,10 @@
-from .routers import auth as auth_router
-from .routers import users as users_router
-from .routers import admin as admin_router
-from .routers import ai as ai_router
-from .routers import generate as generate_router
-from .routers import images as images_router
-from .routers import models as models_router
+from .routers import auth
+from .routers import users
+from .routers import admin
+from .routers import ai
+from .routers import generate
+from .routers import images
+from .routers import models
 from .db import close_db, init_db
 import os
 from contextlib import asynccontextmanager
@@ -38,13 +38,13 @@ app.add_middleware(
     allow_headers=["*"],
 )
 
-app.include_router(auth_router.router)
-app.include_router(users_router.router)
-app.include_router(admin_router.router)
-app.include_router(ai_router.router)
-app.include_router(generate_router.router)
-app.include_router(images_router.router)
-app.include_router(models_router.router)
+app.include_router(auth.router)
+app.include_router(users.router)
+app.include_router(admin.router)
+app.include_router(ai.router)
+app.include_router(generate.router)
+app.include_router(images.router)
+app.include_router(models.router)
 
 
 @app.get("/health", tags=["health"])