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/components/settings/PricingSettings.tsx

@@ -19,7 +19,18 @@
 import { Checkbox } from "../Checkbox";
 import { useEffect, useState, useCallback, useRef, Fragment } from "react";
 import { useTranslation } from "react-i18next";
-import { DollarSign, Plus, Pencil, Trash2, Check, X, RotateCcw, Info } from "lucide-react";
+import { Link } from "react-router-dom";
+import {
+  ArrowRight,
+  DollarSign,
+  Plus,
+  Pencil,
+  Trash2,
+  Check,
+  X,
+  RotateCcw,
+  Info,
+} from "lucide-react";
 import { api } from "../../lib/api";
 import { eventBus } from "../../lib/eventBus";
 import { isRemoteDataRefreshMessage } from "../../lib/remoteDataEvents";
@@ -191,6 +202,29 @@ function PricingInfoTooltip({ vendor }: { vendor: PricingVendor }) {
 
 export type PricingVendor = "claude" | "openai" | "google";
 
+/**
+ * A tool page's pointer to its vendor's table on the one Pricing page — the
+ * table itself lives only there, so a price is never shown (or edited) twice.
+ */
+export function PricingLink({ vendor }: { vendor: PricingVendor }) {
+  const { t } = useTranslation("settings");
+  return (
+    <div className="card flex items-center justify-between gap-4 p-5">
+      <div className="min-w-0">
+        <h3 className="flex items-center gap-2 text-sm font-semibold text-fg-primary">
+          <DollarSign className="h-4 w-4 text-fg-muted" />
+          {t("pricingLink.title")}
+        </h3>
+        <p className="mt-0.5 text-xs text-fg-muted">{t("pricingLink.description")}</p>
+      </div>
+      <Link to={`/settings/pricing#pricing-${vendor}`} className="btn-ghost shrink-0 text-xs">
+        {t("pricingLink.open")}
+        <ArrowRight className="h-3.5 w-3.5" />
+      </Link>
+    </div>
+  );
+}
+
 // Every mounted table's `load`: a change in one reloads them all, and loads
 // fired together share one request.
 const tables = new Set<() => void>();