fix(menubar): add Cycle Theme action under Help menu (closes #453)

src/components/layout/AppLayout.tsx

@@ -10,6 +10,7 @@ import { useConnectionStore } from "../../stores/connectionStore";
 import { useEditorStore } from "../../stores/editorStore";
 import { useResultStore } from "../../stores/resultStore";
 import { useSettingsStore } from "../../stores/settingsStore";
+import { useThemeStore } from "../../stores/themeStore";
 import { AIChatPanel } from "../ai/AIChatPanel";
 import { BackupDialog } from "../backup/BackupDialog";
 import { RestoreDialog } from "../backup/RestoreDialog";
@@ -161,6 +162,18 @@ export function AppLayout() {
         case "check-for-updates":
           void useSettingsStore.getState().checkForUpdates();
           break;
+        case "cycle-theme":
+          // Cycle Dark → Light → System, mirroring Toolbar.cycleTheme so
+          // macOS users get the same one-click action as everyone else.
+          // (refs #453)
+          {
+            const themeStore = useThemeStore.getState();
+            const themeOrder = ["dark", "light", "system"] as const;
+            const idx = themeOrder.indexOf(themeStore.theme);
+            const next = themeOrder[(idx + 1) % themeOrder.length];
+            themeStore.setTheme(next);
+          }
+          break;
         case "about":
           setHelpTab("about");
           setShowShortcuts(true);

src/components/layout/MenuBar.tsx

@@ -57,6 +57,8 @@ const MENUS: MenuDef[] = [
     items: [
       { type: "item", id: "check-for-updates", label: "Check for Updates…" },
       { type: "separator" },
+      { type: "item", id: "cycle-theme", label: "Cycle Theme (Dark / Light / System)" },
+      { type: "separator" },
       { type: "item", id: "keyboard-shortcuts", label: "Keyboard Shortcuts", shortcut: "F1" },
       { type: "separator" },
       { type: "item", id: "about", label: "About SQLPilot" },

src/components/layout/__tests__/MenuBar.test.tsx

@@ -160,4 +160,21 @@ describe("MenuBar", () => {
       expect.objectContaining({ detail: "check-for-updates" }),
     );
   });
+
+  it("includes a 'Cycle Theme' entry under the Help menu (refs #453)", () => {
+    render(<MenuBar />);
+
+    fireEvent.click(screen.getByText("Help"));
+    expect(screen.getByText(/Cycle Theme/)).toBeInTheDocument();
+  });
+
+  it("dispatches 'cycle-theme' menu-action when the entry is clicked", () => {
+    render(<MenuBar />);
+
+    fireEvent.click(screen.getByText("Help"));
+    fireEvent.click(screen.getByText(/Cycle Theme/));
+    expect(dispatchSpy).toHaveBeenCalledWith(
+      expect.objectContaining({ detail: "cycle-theme" }),
+    );
+  });
 });