feat(tray): rebuild the tray menu around apps and their modes

The native menu now lists Claude Code, Claude Desktop, Codex, Gemini CLI
and Grok Build (hidden apps are skipped; additive apps stay out). Each
app row reads "name · mode · provider · quota" and opens a submenu that
states the mode and only offers providers that switching can actually
use: providers that need routing open the app page with the same
needs-routing dialog, official subscriptions are disabled under routing,
and the menu is read-only while failover is on instead of silently
turning failover off. Projects move into the app submenus.

Quota text matches the cards (remaining, "running low" under 10%, no
emoji). A problems section appears only when something needs action:
the routing service is down while apps use it, an app fell back to
direct at startup, or a tray switch failed.

On Windows a left click opens the window and a right click shows the
menu; macOS and Linux keep the menu on left click.

tests/hooks/useTrayNavigation.test.tsx

@@ -0,0 +1,90 @@
+import { renderHook, waitFor } from "@testing-library/react";
+import { http, HttpResponse } from "msw";
+import { describe, expect, it, vi } from "vitest";
+import {
+  parseTrayNavigation,
+  useTrayNavigation,
+} from "@/hooks/useTrayNavigation";
+import { server } from "../msw/server";
+import { emitTauriEvent } from "../msw/tauriMocks";
+
+const TAURI_ENDPOINT = "http://tauri.local";
+
+/** 后端留下的导航：取一次就清空（同 `tray::take_tray_navigation`） */
+function pendingNavigation(initial: unknown) {
+  let pending: unknown = initial;
+  server.use(
+    http.post(`${TAURI_ENDPOINT}/take_tray_navigation`, () => {
+      const value = pending;
+      pending = null;
+      return HttpResponse.json(value as any);
+    }),
+  );
+  return (next: unknown) => {
+    pending = next;
+  };
+}
+
+describe("parseTrayNavigation", () => {
+  it("keeps known apps, sections and intents", () => {
+    expect(
+      parseTrayNavigation({
+        app: "claude",
+        intent: "needsRoute",
+        providerId: "copilot",
+      }),
+    ).toEqual({ app: "claude", intent: "needsRoute", providerId: "copilot" });
+    expect(parseTrayNavigation({ app: "grokbuild", intent: "add" })).toEqual({
+      app: "grokbuild",
+      intent: "add",
+      providerId: undefined,
+    });
+    expect(parseTrayNavigation({ section: "routing" })).toEqual({
+      section: "routing",
+    });
+  });
+
+  it("drops unknown targets and incomplete needs-route requests", () => {
+    expect(parseTrayNavigation(null)).toBeNull();
+    expect(parseTrayNavigation({ app: "nope" })).toBeNull();
+    expect(parseTrayNavigation({ section: "nope" })).toBeNull();
+    expect(parseTrayNavigation({ app: "codex", intent: "needsRoute" })).toEqual(
+      { app: "codex" },
+    );
+  });
+});
+
+describe("useTrayNavigation", () => {
+  it("takes a navigation left before the window existed", async () => {
+    pendingNavigation({ app: "codex" });
+    const onNavigate = vi.fn();
+    renderHook(() => useTrayNavigation(onNavigate));
+    await waitFor(() =>
+      expect(onNavigate).toHaveBeenCalledWith({
+        app: "codex",
+        intent: undefined,
+        providerId: undefined,
+      }),
+    );
+    expect(onNavigate).toHaveBeenCalledTimes(1);
+  });
+
+  it("takes the navigation again on every tray-navigate event", async () => {
+    const leave = pendingNavigation(null);
+    const onNavigate = vi.fn();
+    renderHook(() => useTrayNavigation(onNavigate));
+    // 挂载时取过一次（空的），监听已经挂上
+    await waitFor(() => expect(onNavigate).not.toHaveBeenCalled());
+    await new Promise((resolve) => setTimeout(resolve, 0));
+
+    leave({ app: "claude", intent: "needsRoute", providerId: "copilot" });
+    emitTauriEvent("tray-navigate", null);
+    await waitFor(() =>
+      expect(onNavigate).toHaveBeenCalledWith({
+        app: "claude",
+        intent: "needsRoute",
+        providerId: "copilot",
+      }),
+    );
+  });
+});