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.

docs/OVERVIEW.md

@@ -66,10 +66,12 @@ Internal build — all rights reserved.
   images dragged onto a terminal or a prompt box are uploaded and attached by
   their saved path.
 - **Settings as one page per section** (`/settings/<section>`): a left nav
-  grouped General (General / Data / About / Appearance / Pet / Notifications) /
-  Agents / Routing / Cost / Git, a search box (Ctrl+F) over every section whose
-  results deep-link a row's sub-tab and anchor, a page per installed AI tool, per-vendor model pricing, and which
-  untracked worktrees a workspace's Add folder suggests.
+  grouped General (Appearance — language, theme, pet — / Notifications /
+  System) / Agents (AI tools, one page per installed AI tool, AI Proxy) / Data
+  (Database / Pricing / Snapshots & reports / Git — logins and which untracked
+  worktrees a workspace's Add folder suggests), a search box (Ctrl+F) over every
+  section whose results deep-link a row's sub-tab and anchor. Model prices live
+  only on Pricing; a tool's page links there.
 - **Claude Code + Codex configuration explorer.** Settings hosts one page per
   tool: every plugin, skill, subagent, slash command, MCP server, hook, settings
   file, memory file, marketplace, keybinding and statusline Claude Code knows
@@ -82,7 +84,9 @@ Internal build — all rights reserved.
   OS live) and a theme per mode — dark: Default, Darcula, Apple Dark, Orca Dark;
   light: Default, Apple Light, Canvas, Orca Light. Each mode
   remembers its own theme, so the sidebar's quick toggle swaps between the two.
-  Per-browser only.
+  It also picks the workspace terminals' font: JetBrains Mono (default), the
+  rounded Maple Mono, or the browser's own fixed-width font (which may lack some
+  Vietnamese letters). Per-browser only.
 - **Notification sounds.** Settings → Notifications picks a sound (None, Chime,
   Pop, Alert — off by default) played with every notification shown, and each
   notification type can pick its own.
@@ -209,7 +213,7 @@ agenthub service uninstall     # disable and remove it
 On Linux, `agenthub service install` also tries `loginctl enable-linger` so the service
 starts on a cold boot, before anyone logs in; if that needs elevated rights on
 your machine it prints the `sudo loginctl enable-linger <user>` command to run
-once yourself. The same is a switch in the dashboard — Settings → About →
+once yourself. The same is a switch in the dashboard — Settings → System →
 **Start AgentHub automatically** (off by default; it enables or disables the
 unit and never stops the running server). Plugin installs get it only once
 that switch is on — see