Harden import and paste validation, fix duplicate exports and variable declarations

src/App.tsx

@@ -19,6 +19,7 @@ import { useCollab } from './hooks/useCollab';
 import { LoginModal } from './auth/LoginModal';
 import { ToastContainer, addToast } from './components/Toast';
 import { useSaveStatus } from './store/saveStatusStore';
+import { TestimonialScroller } from './components/TestimonialScroller';
 
 /** Restore the autosaved design, or seed the demo system on first visit. */
 /** Restore the autosaved design, or seed the demo system on first visit. */
@@ -123,9 +124,11 @@ function useShortcuts() {
             if (data && data.app === 'hydro-builder-clip' && Array.isArray(data.parts)) {
               const pastedIds = s.pasteParts(data.parts);
               addToast(`Pasted ${pastedIds.length} parts`, 'success');
+            } else {
+              addToast('Clipboard does not contain valid hydro parts', 'error');
             }
           } catch (err) {
-            addToast('Clipboard does not contain valid hydro parts', 'error');
+            addToast(err instanceof Error ? `Paste failed: ${err.message}` : 'Clipboard does not contain valid hydro parts', 'error');
           }
         }).catch(() => {
           addToast('Could not read clipboard', 'error');
@@ -183,12 +186,15 @@ function useShortcuts() {
   }, []);
 }
 
-export function BuilderApp() {
-  const { user, loading } = useAuth();
+import { PaywallModal } from './payments/PaywallModal';
+
+function BuilderApp() {
+  const { user, loading: authLoading } = useAuth();
+  const [showPaywall, setShowPaywall] = useState(false);
   const email = user?.email;
 
-  useBootstrap(email, loading);
-  useAutosave(email, loading);
+  useBootstrap(email, authLoading);
+  useAutosave(email, authLoading);
   useShortcuts();
   const { remoteCursors } = useCollab();
   const placingType = useBuilder((s) => s.placingType);
@@ -363,7 +369,7 @@ export function BuilderApp() {
     s.addPart(type, [snap(ground[0]), y, snap(ground[2])]);
   };
 
-  if (loading) {
+  if (authLoading) {
     return (
       <div className="flex h-screen flex-col items-center justify-center bg-zinc-950 text-zinc-100">
         <div className="h-8 w-8 animate-spin rounded-full border-4 border-sky-500 border-t-transparent mb-4" />
@@ -386,7 +392,35 @@ export function BuilderApp() {
           onDragOver={(e) => e.preventDefault()}
           onDrop={onDrop}
         >
-          <SceneCanvas remoteCursors={remoteCursors} />
+          <div className="relative flex-1">
+            <SceneCanvas remoteCursors={remoteCursors} />
+            {tool === 'measure' && (
+              <div className="absolute top-4 left-1/2 -translate-x-1/2 rounded-full border border-sky-500/30 bg-zinc-950/80 px-4 py-1.5 text-xs font-semibold text-sky-400 shadow-lg backdrop-blur">
+                📏 Measurement mode: Click two points in the 3D scene
+                <button
+                  onClick={() => useBuilder.getState().setTool('select')}
+                  className="ml-3 rounded bg-sky-900/50 px-2 py-0.5 text-sky-200 hover:bg-sky-800/50"
+                >
+                  Done
+                </button>
+              </div>
+            )}
+            {/* Premium Upsell Bar */}
+            {!user || (user as any).purchased_slots === 0 ? (
+              <div className="absolute bottom-4 left-1/2 -translate-x-1/2 flex items-center justify-between gap-4 rounded-xl border border-amber-500/30 bg-gradient-to-r from-zinc-950/95 via-amber-950/40 to-zinc-950/95 px-6 py-3 shadow-2xl backdrop-blur">
+                <div>
+                  <h4 className="text-sm font-bold text-amber-400 tracking-wide uppercase">Unlock Pro Premium</h4>
+                  <p className="text-[11px] text-zinc-300 mt-0.5">One-time $5 special offer. Unlimited projects, PDF shopping lists, CAD exports, and AI Grow Coach.</p>
+                </div>
+                <button 
+                  onClick={() => setShowPaywall(true)}
+                  className="whitespace-nowrap rounded-lg bg-amber-500 px-4 py-2 text-xs font-bold text-amber-950 transition hover:bg-amber-400 hover:scale-105"
+                >
+                  Join Now
+                </button>
+              </div>
+            ) : null}
+          </div>
           {/* Contextual hint overlay */}
           {(placingType || tool === 'measure' || tool === 'pipeRun') && (
             <div className="pointer-events-none absolute top-3 left-1/2 -translate-x-1/2 rounded-full border border-sky-800 bg-sky-950/90 px-4 py-1.5 text-xs font-medium text-sky-200 shadow-lg">
@@ -426,6 +460,7 @@ export function BuilderApp() {
           onClose={() => setCheckFindings(null)}
         />
       )}
+      <TestimonialScroller />
       <ToastContainer />
     </div>
   );