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/router/index.ts

@@ -110,6 +110,16 @@ const router = createRouter({
           name: 'settings',
           component: () => import('../views/Settings.vue'),
         },
+        {
+          path: 'goals/:goalId',
+          name: 'goal-detail',
+          component: () => import('../views/GoalDetail.vue'),
+        },
+        {
+          path: 'chat',
+          name: 'chat',
+          component: () => import('../views/Chat.vue'),
+        },
         // Containers removed: My Apps serves the same purpose. Redirect old links.
         {
           path: 'containers',