feat(codex): create and customize Codex config from /settings

Adds the Codex config panel (skills/agents/rules/memory/config editing,
mcp/plugins/marketplaces add-remove via the codex CLI) as the last piece
of parity with the Claude Code settings tab, plus the codex_config_changed
WebSocket type the client was missing, and docs for the new
/api/codex-config surface.

client/src/pages/SettingsHub.tsx

@@ -1,6 +1,6 @@
 /**
  * @file SettingsHub.tsx
- * @description Tabbed shell for /settings that hosts the dashboard's own settings plus per-AI-tool configuration panels (Claude Code today, Codex/Cursor reserved), with the active tab kept in the `?tool=` query param.
+ * @description Tabbed shell for /settings that hosts the dashboard's own settings plus per-AI-tool configuration panels (Claude Code and Codex today, Cursor reserved), with the active tab kept in the `?tool=` query param.
  * @author Nguyễn Ngọc Trí Vĩ <vinnt@smartgift.vn>
  */
 import type { ComponentType } from "react";
@@ -10,6 +10,7 @@ import { Boxes, Settings as SettingsIcon, SquareTerminal, MousePointerClick } fr
 import { PageTabs } from "../components/PageTabs";
 import { Settings } from "./Settings";
 import { CcConfig } from "./CcConfig";
+import { CodexConfig } from "./CodexConfig";
 
 interface ToolTab {
   id: string;
@@ -30,7 +31,7 @@ const DASHBOARD_TAB: ToolTab = {
 const TOOL_TABS: ToolTab[] = [
   DASHBOARD_TAB,
   { id: "claude-code", labelKey: "tools.claudeCode", Icon: Boxes, Panel: CcConfig },
-  { id: "codex", labelKey: "tools.codex", Icon: SquareTerminal },
+  { id: "codex", labelKey: "tools.codex", Icon: SquareTerminal, Panel: CodexConfig },
   { id: "cursor", labelKey: "tools.cursor", Icon: MousePointerClick },
 ];