feat: implement backlog plan management and UI enhancements

- Added functionality to save, clear, and load backlog plans within the application.
- Introduced a new API endpoint for clearing saved backlog plans.
- Enhanced the backlog plan dialog to allow users to review and apply changes to their features.
- Integrated dependency management features in the UI, allowing users to select parent and child dependencies for features.
- Improved the graph view with options to manage plans and visualize dependencies effectively.
- Updated the sidebar and settings to include provider visibility toggles for better user control over model selection.

These changes aim to enhance the user experience by providing robust backlog management capabilities and improving the overall UI for feature planning.

apps/ui/src/store/app-store.ts

@@ -606,6 +606,9 @@ export interface AppState {
   opencodeModelsLastFetched: number | null; // Timestamp of last successful fetch
   opencodeModelsLastFailedAt: number | null; // Timestamp of last failed fetch
 
+  // Provider Visibility Settings
+  disabledProviders: ModelProvider[]; // Providers that are disabled and hidden from dropdowns
+
   // Claude Agent SDK Settings
   autoLoadClaudeMd: boolean; // Auto-load CLAUDE.md files using SDK's settingSources option
   skipSandboxWarning: boolean; // Skip the sandbox environment warning dialog on startup
@@ -1021,6 +1024,11 @@ export interface AppActions {
     providers: Array<{ id: string; name: string; authenticated: boolean; authMethod?: string }>
   ) => void;
 
+  // Provider Visibility Settings actions
+  setDisabledProviders: (providers: ModelProvider[]) => void;
+  toggleProviderDisabled: (provider: ModelProvider, disabled: boolean) => void;
+  isProviderDisabled: (provider: ModelProvider) => boolean;
+
   // Claude Agent SDK Settings actions
   setAutoLoadClaudeMd: (enabled: boolean) => Promise<void>;
   setSkipSandboxWarning: (skip: boolean) => Promise<void>;
@@ -1264,6 +1272,7 @@ const initialState: AppState = {
   opencodeModelsError: null,
   opencodeModelsLastFetched: null,
   opencodeModelsLastFailedAt: null,
+  disabledProviders: [], // No providers disabled by default
   autoLoadClaudeMd: false, // Default to disabled (user must opt-in)
   skipSandboxWarning: false, // Default to disabled (show sandbox warning dialog)
   mcpServers: [], // No MCP servers configured by default
@@ -2154,6 +2163,16 @@ export const useAppStore = create<AppState & AppActions>()((set, get) => ({
       ),
     }),
 
+  // Provider Visibility Settings actions
+  setDisabledProviders: (providers) => set({ disabledProviders: providers }),
+  toggleProviderDisabled: (provider, disabled) =>
+    set((state) => ({
+      disabledProviders: disabled
+        ? [...state.disabledProviders, provider]
+        : state.disabledProviders.filter((p) => p !== provider),
+    })),
+  isProviderDisabled: (provider) => get().disabledProviders.includes(provider),
+
   // Claude Agent SDK Settings actions
   setAutoLoadClaudeMd: async (enabled) => {
     const previous = get().autoLoadClaudeMd;