feat(dashboard): unify icons with Lucide Icons library

- Introduce Lucide Icons via CDN for consistent SVG icons
- Replace emoji icons with Lucide SVG icons in sidebar navigation
- Fix Sessions/Explorer icon confusion (📁/📂 → history/folder-tree)
- Update top bar icons (logo, theme toggle, search, refresh)
- Update stats section icons with colored Lucide icons
- Add icon animations support (animate-spin for loading states)
- Update Explorer view with Lucide folder/file icons
- Support dark/light theme icon adaptation

Icon mapping:
- Explorer: folder-tree (was 📂)
- Sessions: history (was 📁)
- Overview: bar-chart-3
- Active: play-circle
- Archived: archive
- Lite Plan: file-edit
- Lite Fix: wrench
- MCP Servers: plug
- Hooks: webhook

ccw/src/templates/dashboard-js/components/theme.js

@@ -6,6 +6,7 @@ function initTheme() {
   const saved = localStorage.getItem('theme') || 'light';
   document.documentElement.setAttribute('data-theme', saved);
   updateThemeIcon(saved);
+  updateHljsTheme(saved);
 
   document.getElementById('themeToggle').addEventListener('click', () => {
     const current = document.documentElement.getAttribute('data-theme');
@@ -13,9 +14,36 @@ function initTheme() {
     document.documentElement.setAttribute('data-theme', next);
     localStorage.setItem('theme', next);
     updateThemeIcon(next);
+    updateHljsTheme(next);
   });
 }
 
 function updateThemeIcon(theme) {
-  document.getElementById('themeToggle').textContent = theme === 'light' ? '🌙' : '☀️';
+  const darkIcon = document.querySelector('.theme-icon-dark');
+  const lightIcon = document.querySelector('.theme-icon-light');
+  if (darkIcon && lightIcon) {
+    if (theme === 'light') {
+      darkIcon.classList.remove('hidden');
+      lightIcon.classList.add('hidden');
+    } else {
+      darkIcon.classList.add('hidden');
+      lightIcon.classList.remove('hidden');
+    }
+  }
+}
+
+function updateHljsTheme(theme) {
+  // Toggle highlight.js theme stylesheets
+  const darkTheme = document.getElementById('hljs-theme-dark');
+  const lightTheme = document.getElementById('hljs-theme-light');
+  
+  if (darkTheme && lightTheme) {
+    if (theme === 'dark') {
+      darkTheme.disabled = false;
+      lightTheme.disabled = true;
+    } else {
+      darkTheme.disabled = true;
+      lightTheme.disabled = false;
+    }
+  }
 }