feat: multi-instance provider support

- provider_configs: add id TEXT PK; migrate existing rows (provider_type becomes id)
- local_files_index: add provider_id column + index; scope all queries per instance
- ProviderConfigRow: add id field; add get_by_id to trait
- LocalIndex:🆕 add provider_id param; all SQL scoped by provider_id
- factory: thread provider_id through build_local_files_bundle
- AppState.local_index: Option<Arc<LocalIndex>> → HashMap<String, Arc<LocalIndex>>
- admin_providers: restructured routes (POST /admin/providers create, PUT/DELETE /{id}, POST /test)
- admin_providers: use row.id as registry key for jellyfin and local_files
- files.rescan: optional ?provider=<id> query param
- frontend: add id to ProviderConfig, update api/hooks, new multi-instance panel UX

k-tv-backend/api/src/state.rs

@@ -9,6 +9,8 @@ use infra::auth::jwt::{JwtConfig, JwtValidator};
 #[cfg(feature = "auth-oidc")]
 use infra::auth::oidc::OidcService;
 use std::collections::VecDeque;
+#[cfg(feature = "local-files")]
+use std::collections::HashMap;
 use std::sync::{Arc, Mutex};
 use tokio::sync::broadcast;
 
@@ -40,9 +42,9 @@ pub struct AppState {
     pub log_history: Arc<Mutex<VecDeque<LogLine>>>,
     /// Repository for persisted in-app activity events.
     pub activity_log_repo: Arc<dyn ActivityLogRepository>,
-    /// Index for the local-files provider, used by the rescan route.
+    /// Indexes for local-files provider instances, keyed by provider instance id.
     #[cfg(feature = "local-files")]
-    pub local_index: Arc<tokio::sync::RwLock<Option<Arc<infra::LocalIndex>>>>,
+    pub local_index: Arc<tokio::sync::RwLock<HashMap<String, Arc<infra::LocalIndex>>>>,
     /// TranscodeManager for FFmpeg HLS transcoding (requires TRANSCODE_DIR).
     #[cfg(feature = "local-files")]
     pub transcode_manager: Arc<tokio::sync::RwLock<Option<Arc<infra::TranscodeManager>>>>,
@@ -147,7 +149,7 @@ impl AppState {
             log_history,
             activity_log_repo,
             #[cfg(feature = "local-files")]
-            local_index: Arc::new(tokio::sync::RwLock::new(None)),
+            local_index: Arc::new(tokio::sync::RwLock::new(HashMap::new())),
             #[cfg(feature = "local-files")]
             transcode_manager: Arc::new(tokio::sync::RwLock::new(None)),
             #[cfg(feature = "local-files")]