feat: add desktop quick open workflow (#925)

Introduce a dedicated Quick Open dialog, wire it to Cmd+P and the macOS app menu, and show file-type icons in quick-open results so file navigation matches the rest of the app.

packages/ui/src/stores/useUIStore.ts

@@ -483,6 +483,7 @@ interface UIStore {
   pendingFileFocusPath: string | null;
   isMobile: boolean;
   isKeyboardOpen: boolean;
+  isQuickOpenOpen: boolean;
   isCommandPaletteOpen: boolean;
   isHelpDialogOpen: boolean;
   isAboutDialogOpen: boolean;
@@ -603,6 +604,8 @@ interface UIStore {
   navigateToDiff: (filePath: string) => void;
   consumePendingDiffFile: () => string | null;
   setIsMobile: (isMobile: boolean) => void;
+  setQuickOpenOpen: (open: boolean) => void;
+  toggleQuickOpen: () => void;
   toggleCommandPalette: () => void;
   setCommandPaletteOpen: (open: boolean) => void;
   toggleHelpDialog: () => void;
@@ -722,6 +725,7 @@ export const useUIStore = create<UIStore>()(
         pendingFileFocusPath: null,
         isMobile: false,
         isKeyboardOpen: false,
+        isQuickOpenOpen: false,
         isCommandPaletteOpen: false,
         isHelpDialogOpen: false,
         isAboutDialogOpen: false,
@@ -1235,6 +1239,14 @@ export const useUIStore = create<UIStore>()(
           set({ isMobile });
         },
 
+        setQuickOpenOpen: (open) => {
+          set({ isQuickOpenOpen: open });
+        },
+
+        toggleQuickOpen: () => {
+          set((state) => ({ isQuickOpenOpen: !state.isQuickOpenOpen }));
+        },
+
         toggleCommandPalette: () => {
           set((state) => ({ isCommandPaletteOpen: !state.isCommandPaletteOpen }));
         },