feat: add local files provider with indexing and rescan functionality

- Implemented LocalFilesProvider to manage local video files.
- Added LocalIndex for in-memory and SQLite-backed indexing of video files.
- Introduced scanning functionality to detect video files and extract metadata.
- Added API endpoints for listing collections, genres, and series based on provider capabilities.
- Enhanced existing routes to check for provider capabilities before processing requests.
- Updated frontend to utilize provider capabilities for conditional rendering of UI elements.
- Implemented rescan functionality to refresh the local files index.
- Added database migration for local files index schema.

k-tv-backend/api/src/routes/mod.rs

@@ -8,6 +8,7 @@ use axum::Router;
 pub mod auth;
 pub mod channels;
 pub mod config;
+pub mod files;
 pub mod iptv;
 pub mod library;
 
@@ -17,6 +18,7 @@ pub fn api_v1_router() -> Router<AppState> {
         .nest("/auth", auth::router())
         .nest("/channels", channels::router())
         .nest("/config", config::router())
+        .nest("/files", files::router())
         .nest("/iptv", iptv::router())
         .nest("/library", library::router())
 }