feat: ConfigSource enum, RwLock provider_registry, is_admin in UserResponse, available_provider_types

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

@@ -32,6 +32,7 @@ pub struct UserResponse {
     pub id: Uuid,
     pub email: String,
     pub created_at: DateTime<Utc>,
+    pub is_admin: bool,
 }
 
 /// JWT token response
@@ -57,6 +58,8 @@ pub struct ConfigResponse {
     pub providers: Vec<ProviderInfo>,
     /// Capabilities of the primary provider — kept for backward compatibility.
     pub provider_capabilities: domain::ProviderCapabilities,
+    /// Provider type strings supported by this build (feature-gated).
+    pub available_provider_types: Vec<String>,
 }
 
 // ============================================================================