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/DEPLOYMENT.md

@@ -260,6 +260,7 @@ DASHBOARD_ANTIGRAVITY_POLL_MS=15000     # agy conversation files → Antigravity
 AGENTHUB_GEMINI_DIR=                    # where agy keeps its data (default ~/.gemini)
 DASHBOARD_CURSOR_POLL_MS=15000          # Cursor agent transcripts → Cursor sessions (no tokens)
 AGENTHUB_CURSOR_DIR=                    # where Cursor keeps its data (default ~/.cursor)
+AGENTHUB_AGY_USAGE=                     # 0 never runs `agy --print /usage` for the Usage panel's Antigravity quota (default on; running agy may update it)
 
 # Pricing and saved settings
 AGENTHUB_PRICING_SYNC=                  # 0|false|off disables automatic pricing from LiteLLM (default on)