Make systemStatsStore access truly lazy in HelpCenterMenuContent by creating store instance inside action function instead of at component initialization time
- Remove navigator fallback since systemStatsStore is the standard
- Default to Windows when OS info not available
- Simplify tests to match new behavior
- More consistent with app architecture
- Create src/constants/urls.ts with centralized URL constants (COMFY_URLS, GITHUB_REPOS, MODEL_SOURCES, DEVELOPER_TOOLS)
- Move runtime domain config to src/config/comfyDomain.ts to allow forkers to customize via env var
- Rename uvMirrors.ts to mirrors.ts for better naming consistency
- Add platform and locale-aware desktop guide URL generation (matching PR #4471)
- Update 10 components to use centralized URL constants
- Add comprehensive unit and e2e tests for URL constants validation
This refactoring improves maintainability by centralizing 150+ hardcoded URLs found across 50+ files into a single organized structure.
