refactor: onboarding, mobile nav, remove maintenance flows

- Onboarding steps guide toward copilot usage, not flow building
- Mobile nav updated to match sidebar (Session History, Guided Flows)
- Remove Step Library from mobile nav
- Remove Maintenance from flow type filter tabs
- Remove Maintenance badge from all tree views (grid, list, table)
- Remove Maintenance create option from CreateFlowDropdown
- Add copilot-first dashboard plan and solutions library spec docs

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

frontend/src/components/layout/AppLayout.tsx

@@ -1,6 +1,6 @@
 import { useEffect, useState, useCallback } from 'react'
 import { useLocation, useNavigate, Link } from 'react-router-dom'
-import { Menu, X, LayoutGrid, Clock, AlertTriangle, GitBranch, Code2, Wand2, BarChart3, Settings, LogOut, Shield, Layers } from 'lucide-react'
+import { Menu, X, LayoutGrid, Clock, AlertTriangle, GitBranch, Code2, Wand2, BarChart3, Settings, LogOut, Shield, FileText } from 'lucide-react'
 import { useAuthStore } from '@/store/authStore'
 import { usePermissions } from '@/hooks/usePermissions'
 import { useUserPreferencesStore } from '@/store/userPreferencesStore'
@@ -52,11 +52,10 @@ export function AppLayout() {
 
   const mobileNavItems = [
     { path: '/', label: 'Dashboard', icon: LayoutGrid },
-    { path: '/sessions', label: 'Active Sessions', icon: Clock },
+    { path: '/sessions', label: 'Session History', icon: Clock },
     { path: '/escalations', label: 'Escalations', icon: AlertTriangle },
-    { path: '/trees', label: 'Flows', icon: GitBranch },
-    { path: '/step-library', label: 'Step Library', icon: Layers },
-    { path: '/scripts', label: 'Scripts', icon: Code2 },
+    { path: '/trees', label: 'Guided Flows', icon: GitBranch },
+    { path: '/scripts', label: 'Scripts', icon: FileText },
     { path: '/script-builder', label: 'Script Builder', icon: Wand2 },
     { path: '/analytics', label: 'Analytics', icon: BarChart3 },
     { path: '/account', label: 'Account', icon: Settings },