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/lib/panePaste.ts

@@ -2,7 +2,8 @@
  * @file panePaste.ts — lets another part of the Workspace page paste text into
  * a workspace's terminal (a diff-line comment from the Changes panel). Every
  * mounted TerminalView registers its run id; the text goes to the pane of that
- * workspace the user focused last, else any of its panes. It is a paste —
+ * workspace focused last — clicked into, or made the Workspace's focused pane
+ * (a tab, Alt+1–4, the sidebar) — else any of its panes. It is a paste —
  * bracketed, so `claude` takes it as one block in its composer — and never an
  * Enter: the user reads it and sends it. Only a pane on SCREEN takes it (one
  * hidden behind a full-width Changes panel or a replay would swallow it