GET /api/mcp/config returns 403 for non-admin users, but the previous
client returned the error body as MCPConfig, causing MCPServerList to
crash with 'Cannot convert undefined or null to object' on
Object.entries(config.mcp_servers).
- api.ts: introduce MCPConfigRequestError; loadMCPConfig and
updateMCPConfig now throw it (carrying status + isAdminRequired)
instead of letting non-2xx bodies leak through as parsed config
- tool-settings-page.tsx: render a friendly 'admin privileges required'
empty state when the React Query error is an admin-required
MCPConfigRequestError; keep MCPServerList resilient with
Object.entries(servers ?? {}) and an empty-state for no servers
- i18n: add settings.tools.adminRequired and settings.tools.empty in
en-US, zh-CN and the Translations type
- tests: cover 403 / 5xx / instanceof / detail-fallback for both
loadMCPConfig and updateMCPConfig in tests/unit/core/mcp/api.test.ts
Refs: #3527
