feat(config): add system configuration module (Phase 3)

Implement the complete erp-config crate with:
- Data dictionaries (CRUD + items management)
- Dynamic menus (tree structure with role filtering)
- System settings (hierarchical: platform > tenant > org > user)
- Numbering rules (concurrency-safe via PostgreSQL advisory_lock)
- Theme and language configuration (via settings store)
- 6 database migrations (dictionaries, menus, settings, numbering_rules)
- Frontend Settings page with 5 tabs (dictionary, menu, numbering, settings, theme)

Refactor: move RBAC functions (require_permission) from erp-auth to erp-core
to avoid cross-module dependencies.

Add 20 new seed permissions for config module operations.

apps/web/src/pages/Settings.tsx

@@ -0,0 +1,20 @@
+import { Tabs } from 'antd';
+import DictionaryManager from './settings/DictionaryManager';
+import MenuConfig from './settings/MenuConfig';
+import NumberingRules from './settings/NumberingRules';
+import SystemSettings from './settings/SystemSettings';
+import ThemeSettings from './settings/ThemeSettings';
+
+const Settings: React.FC = () => {
+  const items = [
+    { key: 'dictionaries', label: '数据字典', children: <DictionaryManager /> },
+    { key: 'menus', label: '菜单配置', children: <MenuConfig /> },
+    { key: 'numbering', label: '编号规则', children: <NumberingRules /> },
+    { key: 'settings', label: '系统参数', children: <SystemSettings /> },
+    { key: 'theme', label: '主题设置', children: <ThemeSettings /> },
+  ];
+
+  return <Tabs defaultActiveKey="dictionaries" items={items} />;
+};
+
+export default Settings;