Add Chinese documentation for custom skills development and reference guide

- Created a new document for custom skills development (`custom.md`) detailing the structure, creation, implementation, and best practices for developing custom CCW skills.
- Added an index document (`index.md`) summarizing all built-in skills, their categories, and usage examples.
- Introduced a reference guide (`reference.md`) providing a quick reference for all 33 built-in CCW skills, including triggers and purposes.

docs/.vitepress/theme/composables/useDynamicIcon.ts

@@ -35,10 +35,16 @@ export const STATUS_COLORS = {
 const STORAGE_KEY_THEME = 'ccw-theme'
 const STORAGE_KEY_COLOR_MODE = 'ccw-color-mode'
 
+/**
+ * Check if running in browser environment
+ */
+const isBrowser = typeof window !== 'undefined' && typeof localStorage !== 'undefined'
+
 /**
  * Get current theme from localStorage or default
  */
 export function getCurrentTheme(): ThemeName {
+  if (!isBrowser) return 'blue'
   const saved = localStorage.getItem(STORAGE_KEY_THEME)
   if (saved && saved in THEME_COLORS) {
     return saved as ThemeName
@@ -50,6 +56,7 @@ export function getCurrentTheme(): ThemeName {
  * Check if dark mode is active
  */
 export function isDarkMode(): boolean {
+  if (!isBrowser) return false
   const mode = localStorage.getItem(STORAGE_KEY_COLOR_MODE) || 'auto'
   const prefersDark = window.matchMedia('(prefers-color-scheme: dark)').matches
   return mode === 'dark' || (mode === 'auto' && prefersDark)