* feat(pages): add Docs page with search, markdown rendering, and i18n support
- Add DocsPage with full-text search modal (⌘K trigger)
- Add MarkdownRenderer with DOMPurify sanitization
- Add bilingual docs content (en/zh) for all sections
- Add shared headingId utility for consistent TOC anchors
- Add search keyboard hints with i18n support
- Update Navbar with Docs navigation link
- Add icon-search.svg asset
- Configure webpack for markdown imports
* fix(pages): address PR #273 code review feedback
- Replace marked.setOptions() with new Marked instance (no global mutation)
- Escape heading ID attribute value to prevent XSS
- Use crypto.randomUUID() for mermaid diagram IDs (no collisions)
- Add cancellation flag for async mermaid renders on unmount
- Move inline <pre> styles to CSS class (only dynamic align-items inline)
- Move @types/dompurify to devDependencies
- Remove @ts-nocheck from docs/index.ts
- Extract getRawContent helper to reduce duplication
- Fix searchDocs fallback consistency (add enDocs fallback)
- Fix heading ID mismatch by stripping markdown links before ID generation
- Separate sidebar chevron (expand) from label (navigate)
- Guard ⌘K shortcut against input/textarea focus interception
