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-frontend/lib/api.ts

@@ -238,8 +238,10 @@ export const api = {
   },
 
   files: {
-    rescan: (token: string) =>
-      request<{ items_found: number }>("/files/rescan", { method: "POST", token }),
+    rescan: (token: string, provider?: string) => {
+      const qs = provider ? `?provider=${encodeURIComponent(provider)}` : "";
+      return request<{ items_found: number }>(`/files/rescan${qs}`, { method: "POST", token });
+    },
   },
 
   transcode: {
@@ -268,26 +270,35 @@ export const api = {
       getProviders: (token: string) =>
         request<ProviderConfig[]>("/admin/providers", { token }),
 
+      createProvider: (
+        token: string,
+        payload: { id: string; provider_type: string; config_json: Record<string, string>; enabled: boolean },
+      ) =>
+        request<ProviderConfig>("/admin/providers", {
+          method: "POST",
+          body: JSON.stringify(payload),
+          token,
+        }),
+
       updateProvider: (
         token: string,
-        type: string,
+        id: string,
         payload: { config_json: Record<string, string>; enabled: boolean },
       ) =>
-        request<ProviderConfig>(`/admin/providers/${type}`, {
+        request<ProviderConfig>(`/admin/providers/${id}`, {
           method: "PUT",
           body: JSON.stringify(payload),
           token,
         }),
 
-      deleteProvider: (token: string, type: string) =>
-        request<void>(`/admin/providers/${type}`, { method: "DELETE", token }),
+      deleteProvider: (token: string, id: string) =>
+        request<void>(`/admin/providers/${id}`, { method: "DELETE", token }),
 
       testProvider: (
         token: string,
-        type: string,
-        payload: { config_json: Record<string, string>; enabled: boolean },
+        payload: { provider_type: string; config_json: Record<string, string> },
       ) =>
-        request<ProviderTestResult>(`/admin/providers/${type}/test`, {
+        request<ProviderTestResult>("/admin/providers/test", {
           method: "POST",
           body: JSON.stringify(payload),
           token,