feat: add flow type selection to Flow Assist entry points

- CreateFlowDropdown now shows "Build with Flow Assist" under each flow type
- Library page "Flow Assist" button respects current type filter
- Clean up unused AIFlowBuilderModal references

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

frontend/src/pages/TreeLibraryPage.tsx

@@ -22,7 +22,6 @@ import { usePermissions } from '@/hooks/usePermissions'
 import { useUserPreferencesStore } from '@/store/userPreferencesStore'
 import { usePinnedFlowsStore } from '@/store/pinnedFlowsStore'
 import { useCachedQuota } from '@/hooks/useCachedQuota'
-import { AIFlowBuilderModal } from '@/components/ai-builder/AIFlowBuilderModal'
 import { CreateFlowDropdown } from '@/components/common/CreateFlowDropdown'
 import { Spinner } from '@/components/common/Spinner'
 import { EmptyState } from '@/components/common/EmptyState'
@@ -83,7 +82,7 @@ export function TreeLibraryPage() {
   const [exportTarget, setExportTarget] = useState<TreeListItem | null>(null)
 
   // AI builder state
-  const [showAIBuilder, setShowAIBuilder] = useState(false)
+
   const { aiEnabled } = useCachedQuota()
 
   // Pin store
@@ -286,7 +285,7 @@ export function TreeLibraryPage() {
               <div className="flex items-center gap-2">
                 {aiEnabled && (
                   <button
-                    onClick={() => navigate('/ai/chat')}
+                    onClick={() => navigate(typeFilter === 'procedural' || typeFilter === 'maintenance' ? `/ai/chat?type=${typeFilter}` : '/ai/chat')}
                     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" />
@@ -302,7 +301,7 @@ export function TreeLibraryPage() {
                 </button>
                 <CreateFlowDropdown
                   aiEnabled={aiEnabled}
-                  onOpenAIBuilder={() => setShowAIBuilder(true)}
+
                   label="Create New"
                 />
               </div>
@@ -588,13 +587,6 @@ export function TreeLibraryPage() {
         isLoading={isDeleting}
       />
 
-      {/* AI Builder Modal */}
-      {showAIBuilder && (
-        <AIFlowBuilderModal
-          isOpen={showAIBuilder}
-          onClose={() => setShowAIBuilder(false)}
-        />
-      )}
 
       {forkTarget && (
         <ForkModal