feat(ai-tools): drop OpenCode and Grok Build

- opencode.json / grok.json leave the built-in catalog; opencode-usage.js,
  its poller, transcript branch and table creation go with it (existing
  tables and session rows stay as history).
- A Grok payload reaching the Claude hook route (Grok runs the Claude hooks
  itself) is dropped instead of recorded as tool = 'grok'.
- quota.js no longer reads Grok or OpenCode Go logins.
- Redone on v2.8.22 from c6b2892 (feat/grok-usage, never merged).

client/src/components/StatusBar.tsx

@@ -50,9 +50,7 @@ const QUOTA_TOOL_LABEL: Record<ToolQuota["id"], string> = {
   codex: "Codex",
   antigravity: "Antigravity",
   cursor: "Cursor",
-  grok: "Grok",
   kimi: "Kimi",
-  opencode: "OpenCode Go",
 };
 
 function localDate(d = new Date()): string {