feat: implement three-mode UI system (Easy / Pro / Chat)

Add switchable UI modes with conditional rendering:
- Easy mode: goal-based interface with 7 guided workflows
- Pro mode: current technical interface preserved with Quick Start Goals
- Chat mode: AIUI placeholder for future integration

New components: ModeSwitcher, EasyHome, GoalDetail wizard, Chat placeholder
New stores: uiMode (mode persistence), goals (progress tracking)
New data: goal definitions catalog, helpTree goals section
Modified: Dashboard (reactive nav), Home (mode dispatcher), Settings (mode picker),
Router (goal/chat routes), Spotlight (goal search integration)

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

neode-ui/src/components/SpotlightSearch.vue

@@ -237,7 +237,7 @@ function selectHelpItem(section: { id: string }, item: { id: string; label: stri
   }
 }
 
-function selectRecent(item: { id: string; label: string; path?: string; type: 'navigate' | 'learn' | 'action' }) {
+function selectRecent(item: { id: string; label: string; path?: string; type: 'navigate' | 'learn' | 'action' | 'goal' }) {
   spotlightStore.close()
   if (item.path === '__cli__') {
     cliStore.open()