Refactor workflow-lite-planex documentation to standardize phase naming and improve clarity

- Updated phase references in SKILL.md and 01-lite-plan.md to use "LP-Phase" prefix for consistency.
- Added critical context isolation note in 01-lite-plan.md to clarify phase invocation rules.
- Enhanced execution process descriptions to reflect updated phase naming conventions.

Improve error handling in frontend routing

- Introduced ChunkErrorBoundary component to handle lazy-loaded chunk load failures.
- Wrapped lazy-loaded routes with error boundary and suspense for better user experience.
- Created PageSkeleton component for loading states in lazy-loaded routes.

Sanitize header values in notification routes

- Added regex validation for header values to prevent XSS attacks by allowing only printable ASCII characters.

Enhance mobile responsiveness in documentation styles

- Updated CSS breakpoints to use custom properties for better maintainability.
- Improved layout styles across various components to ensure consistent behavior on mobile devices.

docs/.vitepress/theme/styles/demo.css

@@ -35,7 +35,7 @@
 }
 
 /* Responsive design */
-@media (max-width: 768px) {
+@media (max-width: var(--bp-sm)) {
   .demo-header {
     flex-direction: column;
     align-items: flex-start;