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/SERVER-MODE.md

@@ -115,7 +115,8 @@ Workspaces made before server mode, or by the host account, have none.
   session a member owns (its page, transcript, events or cost), the read is
   written to the audit log: `agenthub users audit`, or `GET /api/users/audit`.
 - `GET /api/users` (admin/analyst) lists every account with its workspaces,
-  sessions, and the tokens and $ it used in the last 7 and 30 days.
+  sessions, and the tokens and $ it used in the last 7 and 30 days — the
+  Users page in the sidebar shows it, with the audit log under it.
 
 A member also cannot open the host's own configuration, or any view across all
 users: Claude Code / Codex config (except the command and skill lists the
@@ -183,7 +184,15 @@ apart, not agents.
 
 ## Accounts
 
-Accounts are managed from the host's shell, never from a web route:
+An admin manages accounts on the **Users** page (sidebar; admins and analysts
+see it, an analyst only reads): add a user, change a role, disable or enable,
+reset a password, give a workspace. Every change asks for the admin's OWN
+password again — the server refuses without it (`EREAUTH`, and `ETOOMANY`
+after 10 wrong tries in 15 minutes) — an admin can never demote or disable
+themselves (`ESELF`), and each change is written to the audit log. In local
+mode these routes refuse (`ELOCALMODE`): there is no login to check.
+
+The same from the host's shell:
 
 ```bash
 agenthub users list