Fix browser-local Project V2 cloud miss

app/api/projects/v2/route.ts

@@ -178,7 +178,10 @@ export async function GET(request: NextRequest) {
       account.identity,
       projectId(request.nextUrl.searchParams.get("id")),
     );
-    if (!stored) return json({ error: "Project V2 snapshot was not found." }, 404);
+    // A missing cloud snapshot is an expected state for browser-local projects.
+    // Return a successful empty receipt so Chromium does not surface a noisy
+    // failed-resource console error while Studio falls back to its local copy.
+    if (!stored) return json({ found: false });
     return json(stored);
   } catch (error) {
     return responseError(error);

lib/project-v2-sync-client.ts

@@ -56,6 +56,7 @@ export async function loadProjectV2FromCloud(projectId: string): Promise<{
   if (response.status === 404) return null;
   const value = await responseValue(response);
   if (!response.ok) throw syncError(response, value);
+  if (value.found === false) return null;
   if (!value.project || typeof value.project !== "object" || !Number.isSafeInteger(value.storageRevision)) {
     throw new ProjectV2SyncError({ message: "Project V2 cloud sync returned an invalid snapshot.", status: 502 });
   }

tests/vercel-sandbox-runtime-cleanup.test.mjs

@@ -192,6 +192,14 @@ test("Project V2 accepts the browser-visible host behind a trusted same-origin p
   assert.equal((await response.json()).storageRevision, 1);
 });
 
+test("missing Project V2 reads return a successful empty receipt without a browser 404", async () => {
+  globalThis.__DROPS_STUDIO_LOCAL_PROJECT_V2__?.clear();
+  const { cookie } = guestSession();
+  const response = await getProjectV2(getRequest("browser-local-only-project", cookie));
+  assert.equal(response.status, 200);
+  assert.deepEqual(await response.json(), { found: false });
+});
+
 test("Project V2 deletion fails closed and retains storage when Sandbox destroy fails", async () => {
   globalThis.__DROPS_STUDIO_LOCAL_PROJECT_V2__?.clear();
   globalThis.__DROPS_STUDIO_LOCAL_PROJECT_V2_RELEASE_RECEIPTS__?.clear();