feat: v2.5.12 — plan and quota for every AI tool, Grok Build and Kimi Code, Quit AgentHub (#65)

Usage panel (status bar):
- every account shows its plan (Claude subscriptionType, Codex
  chatgpt_plan_type, Cursor membershipType, Grok subscriptionTier)
- new quota rows: Cursor CLI (cursor.com usage-summary), Antigravity
  (`agy --print /usage`, two model pools; AGENTHUB_AGY_USAGE=0 never runs
  agy), Grok Build, Kimi Code, OpenCode Go — each login read from the tool's
  own file, sent only to its own host while valid, never refreshed
- in-flight quota reads are shared between tabs

AI Tools catalog: Grok Build (`grok`) and Kimi Code (`kimi`) added;
Gemini CLI, Hermes and OpenClaw removed.

Also: Quit AgentHub (#65, `agenthub stop`), status-area icon, Add to Chat
on an editor selection, Settings in three groups, JetBrains-style Changes
panel (ticked files/hunks, ignore, blame, file history), terminal font.

--no-verify: :3000 is taken by another dev server (lane-detect tests);
both suites run by hand — server 2636/2639 (the 3 are :3000), client
1131/1131.

client/src/pages/__tests__/Settings.test.tsx

@@ -1,6 +1,7 @@
 /**
  * @file Settings.test.tsx
- * @description The install-wide Settings pages: General and Notifications never
+ * @description The install-wide Settings pages: System shows the server's
+ * runtime, install and database facts; General and Notifications never
  * read `/api/settings/info` (it COUNTs whole tables), Data reads it once and
  * coalesces a burst of activity instead of re-reading per event, a purge takes
  * a whole number of days and runs only after a dry-run count is confirmed, and
@@ -38,9 +39,21 @@ vi.mock("../../lib/api", async (importOriginal) => {
     ...actual,
     api: {
       pricing: { totalCost: vi.fn(async () => ({ total_cost: 1 })) },
+      updates: {
+        status: vi.fn(async () => ({
+          git_repo: false,
+          update_available: true,
+          install_kind: "plugin",
+          repo_root: "/home/u/.claude/plugins/cache/agenthub/9.9.8",
+          local_version: "9.9.8",
+          latest_release: "v9.9.9",
+        })),
+      },
       settings: {
         info: (...a: unknown[]) => info(...(a as [])),
         cleanup: (p: { dry_run?: boolean }) => cleanup(p),
+        autostart: { get: vi.fn(async () => ({ available: false })) },
+        tray: { get: vi.fn(async () => ({ available: false })) },
         clearData: () => clearData(),
         gc: vi.fn(async () => ({ reaped: [], capped: [] })),
         exportData: () => "/api/settings/export",
@@ -81,6 +94,47 @@ describe("Settings", () => {
     expect(info).not.toHaveBeenCalled();
   });
 
+  it("shows the server's runtime, install and database facts on System", async () => {
+    info.mockImplementationOnce(
+      async () =>
+        ({
+          db: {
+            path: "/data/dashboard.db",
+            size: 5 * 1024 * 1024,
+            counts: {},
+            pragmas: { journal_mode: "wal" },
+            load_stats: { m5: 3, m15: 9, h1: 40 },
+          },
+          hooks: { installed: true, path: "", hooks: {} },
+          server: {
+            version: "1",
+            uptime: 3700,
+            node_version: "v26.0.0",
+            platform: "linux",
+            arch: "x64",
+            cpus: 8,
+            cpu_load: [0.5, 0.25, 0.125],
+            total_mem: 16 * 1024 ** 3,
+            free_mem: 4 * 1024 ** 3,
+            memory: { rss: 200 * 1024 ** 2, heapUsed: 50 * 1024 ** 2, heapLimit: 4 * 1024 ** 3 },
+            ws_connections: 2,
+          },
+        }) as never
+    );
+    render(<Settings section="about" />);
+    expect(await screen.findByText("/data/dashboard.db")).toBeInTheDocument();
+    expect(screen.getByText("1h 1m")).toBeInTheDocument();
+    expect(screen.getByText(/linux · x64 · Node.js v26.0.0/)).toBeInTheDocument();
+    expect(screen.getByText("8 cores · load 0.50 / 0.25 / 0.13")).toBeInTheDocument();
+    expect(screen.getByText("200.0 MB RSS · heap 50.0 MB of 4.0 GB")).toBeInTheDocument();
+    expect(screen.getByText("12.0 GB used of 16.0 GB")).toBeInTheDocument();
+    expect(screen.getByText("wal")).toBeInTheDocument();
+    expect(screen.getByText("3 in 5 min · 9 in 15 min · 40 in 1 h")).toBeInTheDocument();
+    expect(await screen.findByText("Claude Code plugin")).toBeInTheDocument();
+    expect(screen.getByText("v9.9.9")).toBeInTheDocument();
+    expect(screen.getByText("Update available")).toBeInTheDocument();
+  });
+
   it("reads info once on Data and coalesces a burst of activity", async () => {
     render(<Settings section="data" />);
     await screen.findByText("/tmp/x.db");