fix: add glassmorphism to AI prompt dialog + maintenance Flow Assist button

- Use .glass-card-static on AIPromptDialog card for consistent design system
- Add "Build with Flow Assist" button to maintenance section in CreateFlowDropdown

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

frontend/src/components/common/CreateFlowDropdown.tsx

@@ -149,6 +149,22 @@ export function CreateFlowDropdown({
                 <div className="text-xs text-muted-foreground">Scheduled multi-target tasks</div>
               </div>
             </Link>
+            {aiEnabled && (
+              <button
+                type="button"
+                onClick={() => {
+                  setShowMenu(false)
+                  setAiPromptFlowType('maintenance')
+                  setAiPromptOpen(true)
+                }}
+                className="flex w-full items-center gap-3 rounded-md px-3 py-2 text-sm text-foreground hover:bg-accent"
+              >
+                <Sparkles className="h-3.5 w-3.5 text-primary ml-0.5" />
+                <div className="text-left">
+                  <div className="text-xs text-primary font-medium">Build with Flow Assist</div>
+                </div>
+              </button>
+            )}
           </div>
         </>
       )}

frontend/src/components/editor-ai/AIPromptDialog.tsx

@@ -50,7 +50,7 @@ export function AIPromptDialog({
       />
 
       {/* Dialog */}
-      <div className="relative w-full max-w-lg rounded-2xl border border-border bg-card p-6 shadow-xl">
+      <div className="glass-card-static relative w-full max-w-lg p-6 shadow-xl">
         <div className="flex items-center gap-2 mb-4">
           <Sparkles className="h-5 w-5 text-primary" />
           <h2 className="text-lg font-heading font-semibold text-foreground">