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/index.js

@@ -294,6 +294,8 @@ function startServer(app, port) {
       // server even when it bound a non-default port (the desktop app falls
       // back off 4820 when that port is already taken).
       writeServerInfo(port);
+      // A server that starts ends a Quit: the bootstrap may start it again.
+      require("./lib/quit").clearQuit();
       const sharedDbPeers = peersSharingDataDir();
       if (sharedDbPeers.length > 0) {
         const peerPorts = sharedDbPeers.map((p) => p.port).join(", ");
@@ -1101,6 +1103,8 @@ if (require.main === module) {
     startServer(app, PORT).then((server) => {
       httpServer = server;
       startBackgroundServices();
+      // The status-area icon (server/lib/tray.js) — production servers only.
+      require("./lib/tray").startTrayWatch();
     });
   });