* feat(api-docs): enhance API documentation with missing endpoints, search, collapse, and route sync test
- Add 29 undocumented routes across 4 new sections (Settings, Xray Settings,
Subscription Server, WebSocket) plus 4 missing Server API endpoints
- Fix inaccuracies: history metric keys, node metric keys, VLESS enc description
- Add response schemas to 15+ key endpoints
- Add search bar and expand/collapse all controls to the docs page
- Add collapsible endpoint sections with endpoint count
- Add Go test (TestAPIRoutesDocumented) to verify all Go routes are documented
* feat(api-docs): add JSON syntax highlighting and top-right copy button to code blocks
* fix(api-docs): use distinct colors for JSON syntax highlighting (green strings, amber numbers)
* feat(api-docs): add request body examples, error responses, WebSocket message types, and subscription response headers
* fix(api-docs): use ClipboardManager.copyText instead of copy to fix API token copy button
