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.

server/lib/tray.js

@@ -0,0 +1,150 @@
+/**
+ * @file tray.js — the AgentHub icon in the OS status area (GNOME top bar,
+ * macOS menu bar, Windows notification area), like 9router's. The icon is its
+ * own process (`scripts/tray.js`) so a server restart or a Quit never takes it
+ * away — after a Quit it is how the user starts AgentHub again. A production
+ * server keeps it alive (`startTrayWatch`): ON by default, OFF once the user
+ * hides it (the flag `<data dir>/runtime/tray-off`, written by Settings →
+ * System or the icon's own "Hide this icon"; nothing turns it back on but the
+ * user). On Linux it waits for a graphical session — a server started at boot
+ * has no DISPLAY until someone logs in. Never in server mode.
+ * @author Nguyễn Ngọc Trí Vĩ <vinnt@smartgift.vn>
+ */
+
+const fs = require("fs");
+const path = require("path");
+const { getDataDir } = require("./claude-home");
+
+const ROOT = path.resolve(__dirname, "..", "..");
+const CHECK_MS = 60_000;
+const MAX_FAILED_STARTS = 3;
+const HEARTBEAT_MS = 5_000;
+
+const runtime = () => path.join(getDataDir(), "runtime");
+const offPath = () => path.join(runtime(), "tray-off");
+const pidPath = () => path.join(runtime(), "tray.json");
+
+function isEnabled() {
+  return !fs.existsSync(offPath());
+}
+
+/**
+ * `{pid, root}` of the live tray process, or null. The icon touches its file
+ * on every poll (`HEARTBEAT_MS`), so a file left by a crash or a reboot goes
+ * stale and its pid — by then possibly another program's — is never signalled.
+ */
+function liveTray() {
+  try {
+    if (Date.now() - fs.statSync(pidPath()).mtimeMs > 6 * HEARTBEAT_MS) return null;
+    const rec = JSON.parse(fs.readFileSync(pidPath(), "utf8"));
+    process.kill(rec.pid, 0);
+    return rec;
+  } catch {
+    return null;
+  }
+}
+
+function writePid(pid, root = ROOT) {
+  fs.mkdirSync(runtime(), { recursive: true });
+  fs.writeFileSync(pidPath(), JSON.stringify({ pid, root }), "utf8");
+}
+
+function stopTray() {
+  const rec = liveTray();
+  if (!rec) return;
+  try {
+    process.kill(rec.pid, "SIGTERM");
+  } catch {
+    /* already gone */
+  }
+}
+
+/** The environment the icon needs to reach the desktop, or null when there is none. */
+function guiEnv() {
+  if (process.platform !== "linux") return {};
+  const env = require("./desktop-env").desktopEnv();
+  return env.DISPLAY || env.WAYLAND_DISPLAY ? env : null;
+}
+
+function status() {
+  const { isServerMode } = require("./auth");
+  return {
+    available: !isServerMode() && guiEnv() !== null,
+    enabled: isEnabled(),
+    running: liveTray() !== null,
+  };
+}
+
+let failedStarts = 0;
+
+/**
+ * Starts the icon when it should be up and is not. `replace` (once, at server
+ * start) retires an icon still running from another install root — the
+ * previous plugin build, whose cache directory is about to be pruned.
+ */
+function ensureTray({ replace = false, spawn = require("child_process").spawn } = {}) {
+  if (!isEnabled() || failedStarts >= MAX_FAILED_STARTS) return "skipped";
+  const live = liveTray();
+  if (live && !(replace && live.root !== ROOT)) return "running";
+  const env = guiEnv();
+  if (!env) return "no-gui";
+  if (live) stopTray();
+  const started = Date.now();
+  const child = spawn(process.execPath, [path.join(ROOT, "scripts", "tray.js")], {
+    cwd: ROOT,
+    detached: true,
+    stdio: "ignore",
+    env: { ...process.env, ...env },
+  });
+  child.on("error", () => failedStarts++);
+  // An icon that dies at once (no tray host, a binary the OS refuses) is not
+  // retried forever: three quick deaths and this server leaves it alone.
+  child.on("exit", () => {
+    if (Date.now() - started < 10_000) failedStarts++;
+  });
+  child.unref();
+  return "started";
+}
+
+function setEnabled(on, opts) {
+  if (on) {
+    fs.rmSync(offPath(), { force: true });
+    failedStarts = 0;
+    ensureTray(opts);
+  } else {
+    fs.mkdirSync(runtime(), { recursive: true });
+    fs.writeFileSync(offPath(), `${new Date().toISOString()}\n`, "utf8");
+    stopTray();
+  }
+  return status();
+}
+
+function startTrayWatch() {
+  if (process.env.NODE_ENV !== "production" || require("./auth").isServerMode()) return;
+  try {
+    ensureTray({ replace: true });
+  } catch {
+    /* an icon is never worth a server crash */
+  }
+  setInterval(() => {
+    try {
+      ensureTray();
+    } catch {
+      /* same */
+    }
+  }, CHECK_MS).unref();
+}
+
+module.exports = {
+  isEnabled,
+  liveTray,
+  writePid,
+  stopTray,
+  status,
+  ensureTray,
+  setEnabled,
+  startTrayWatch,
+  offPath,
+  pidPath,
+  HEARTBEAT_MS,
+};