feat: rename AI builder to "Flow Assist" and add sidebar nav item

- Rename all "Build with AI" labels to "Flow Assist"
- Update CreateFlowDropdown description to "AI-powered flow builder"
- Add Flow Assist nav item with Sparkles icon to sidebar (both
  expanded and collapsed states)
- Update AIFlowBuilderModal titles for consistency

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

frontend/src/components/ai-builder/AIFlowBuilderModal.tsx

@@ -98,7 +98,7 @@ export function AIFlowBuilderModal({ isOpen, onClose }: AIFlowBuilderModalProps)
   const getTitle = () => {
     switch (phase) {
       case 'foundation':
-        return 'Build with AI'
+        return 'Flow Assist'
       case 'scaffolding':
       case 'generating':
         return 'AI Scaffold'
@@ -107,9 +107,9 @@ export function AIFlowBuilderModal({ isOpen, onClose }: AIFlowBuilderModalProps)
       case 'reviewing':
         return 'Review & Assemble'
       case 'error':
-        return 'AI Flow Builder'
+        return 'Flow Assist'
       default:
-        return 'Build with AI'
+        return 'Flow Assist'
     }
   }
 

frontend/src/components/ai-chat/ChatToolbar.tsx

@@ -27,7 +27,7 @@ export function ChatToolbar({
       <div className="flex items-center gap-3">
         <div className="flex items-center gap-2 text-sm font-medium text-foreground">
           <Sparkles className="h-4 w-4 text-primary" />
-          Build with AI
+          Flow Assist
         </div>
         <PhaseIndicator currentPhase={currentPhase} />
       </div>

frontend/src/components/common/CreateFlowDropdown.tsx

@@ -79,8 +79,8 @@ export function CreateFlowDropdown({
                 >
                   <Sparkles className="h-4 w-4 text-primary" />
                   <div className="text-left">
-                    <div className="font-medium">Build with AI</div>
-                    <div className="text-xs text-muted-foreground">AI-assisted flow creation</div>
+                    <div className="font-medium">Flow Assist</div>
+                    <div className="text-xs text-muted-foreground">AI-powered flow builder</div>
                   </div>
                 </button>
               </>

frontend/src/components/layout/Sidebar.tsx

@@ -1,5 +1,5 @@
 import { useEffect, useState } from 'react'
-import { LayoutGrid, Box, PenLine, Clock, FileText, Bookmark, BarChart3, Settings, PanelLeftClose, PanelLeftOpen, MessageSquareText } from 'lucide-react'
+import { LayoutGrid, Box, PenLine, Clock, FileText, Bookmark, BarChart3, Settings, PanelLeftClose, PanelLeftOpen, MessageSquareText, Sparkles } from 'lucide-react'
 import { cn } from '@/lib/utils'
 import { useUserPreferencesStore } from '@/store/userPreferencesStore'
 import { usePinnedFlowsStore } from '@/store/pinnedFlowsStore'
@@ -75,6 +75,7 @@ export function Sidebar() {
             <NavItem href="/my-trees" icon={PenLine} label="Flow Editor" collapsed />
             <NavItem href="/sessions" icon={Clock} label="Sessions" badge={activeSessionCount || undefined} collapsed />
             <NavItem href="/shares" icon={FileText} label="Exports" collapsed />
+            <NavItem href="/ai/chat" icon={Sparkles} label="Flow Assist" collapsed />
             <NavItem href="/step-library" icon={Bookmark} label="Step Library" collapsed />
             <NavItem href="/analytics" icon={BarChart3} label="Analytics" collapsed />
             <NavItem href="/feedback" icon={MessageSquareText} label="Feedback" collapsed />
@@ -105,6 +106,7 @@ export function Sidebar() {
             <NavItem href="/my-trees" icon={PenLine} label="Flow Editor" />
             <NavItem href="/sessions" icon={Clock} label="Sessions" badge={activeSessionCount || undefined} />
             <NavItem href="/shares" icon={FileText} label="Exports" />
+            <NavItem href="/ai/chat" icon={Sparkles} label="Flow Assist" />
             <NavItem href="/step-library" icon={Bookmark} label="Step Library" />
             <NavItem href="/analytics" icon={BarChart3} label="Analytics" />
           </div>

frontend/src/pages/MyTreesPage.tsx

@@ -191,8 +191,8 @@ export function MyTreesPage() {
                       >
                         <Sparkles className="h-4 w-4 text-primary" />
                         <div className="text-left">
-                          <div className="font-medium">Build with AI</div>
-                          <div className="text-xs text-muted-foreground">AI-assisted flow creation</div>
+                          <div className="font-medium">Flow Assist</div>
+                          <div className="text-xs text-muted-foreground">AI-powered flow builder</div>
                         </div>
                       </button>
                     </>

frontend/src/pages/TreeLibraryPage.tsx

@@ -279,7 +279,7 @@ export function TreeLibraryPage() {
                     className="flex items-center gap-2 rounded-lg bg-gradient-brand px-4 py-2 text-sm font-medium text-white shadow-lg shadow-primary/20 hover:opacity-90 transition-opacity"
                   >
                     <Sparkles className="h-4 w-4" />
-                    Build with AI
+                    Flow Assist
                   </button>
                 )}
                 <CreateFlowDropdown