fix: content-type fallback, replicate polling/validation, atomic gallery append

- fal.ts: Use model capabilities to determine fallback content-type
  (video/mp4 vs image/png) instead of defaulting to video for all models
- replicate.ts: Increase polling timeout to 10 min for video models;
  filter output array to valid strings before URL validation
- nanoBananaExecutor.ts: Replace read-modify-write on outputGallery with
  atomic appendOutputGalleryImage using Zustand set() callback

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

src/app/api/generate/providers/fal.ts

@@ -494,7 +494,8 @@ export async function generateWithFalQueue(
         };
       }
 
-      const contentType = mediaResponse.headers.get("content-type") || "video/mp4";
+      const isVideoModel = input.model.capabilities.some(c => c.includes("video"));
+      const contentType = mediaResponse.headers.get("content-type") || (isVideoModel ? "video/mp4" : "image/png");
       const isVideo = contentType.startsWith("video/");
 
       const mediaArrayBuffer = await mediaResponse.arrayBuffer();

src/app/api/generate/providers/replicate.ts

@@ -156,8 +156,9 @@ export async function generateWithReplicate(
   const prediction = await createResponse.json();
   console.log(`[API:${requestId}] Prediction created: ${prediction.id}`);
 
-  // Poll for completion
-  const maxWaitTime = 5 * 60 * 1000; // 5 minutes
+  // Poll for completion — video models get a longer timeout
+  const isVideoModel = input.model.capabilities.some(c => c.includes("video"));
+  const maxWaitTime = isVideoModel ? 10 * 60 * 1000 : 5 * 60 * 1000;
   const pollInterval = 1000; // 1 second
   const startTime = Date.now();
 
@@ -172,7 +173,7 @@ export async function generateWithReplicate(
     if (Date.now() - startTime > maxWaitTime) {
       return {
         success: false,
-        error: `${input.model.name}: Generation timed out after 5 minutes. Video models may take longer - try again.`,
+        error: `${input.model.name}: Generation timed out after ${maxWaitTime / 60000} minutes.`,
       };
     }
 
@@ -225,8 +226,11 @@ export async function generateWithReplicate(
     };
   }
 
-  // Output can be a single URL string or an array of URLs
-  const outputUrls: string[] = Array.isArray(output) ? output : [output];
+  // Output can be a single URL string or an array — filter to valid strings only
+  const rawOutputs = Array.isArray(output) ? output : [output];
+  const outputUrls: string[] = rawOutputs.filter(
+    (v): v is string => typeof v === "string" && v.length > 0
+  );
 
   if (outputUrls.length === 0) {
     return {

src/store/execution/__tests__/generateVideoExecutor.test.ts

@@ -61,6 +61,7 @@ function makeCtx(
     generationsPath: null,
     saveDirectoryPath: null,
     trackSaveGeneration: vi.fn(),
+    appendOutputGalleryImage: vi.fn(),
     get: vi.fn(),
     ...overrides,
   };

src/store/execution/__tests__/llmGenerateExecutor.test.ts

@@ -61,6 +61,7 @@ function makeCtx(
     generationsPath: null,
     saveDirectoryPath: null,
     trackSaveGeneration: vi.fn(),
+    appendOutputGalleryImage: vi.fn(),
     get: vi.fn(),
     ...overrides,
   };

src/store/execution/__tests__/nanoBananaExecutor.test.ts

@@ -71,6 +71,7 @@ function makeCtx(
     generationsPath: null,
     saveDirectoryPath: null,
     trackSaveGeneration: vi.fn(),
+    appendOutputGalleryImage: vi.fn(),
     get: vi.fn().mockReturnValue({
       edges: [],
       nodes: [node],
@@ -341,8 +342,6 @@ describe("executeNanoBanana", () => {
 
     await executeNanoBanana(ctx);
 
-    expect(ctx.updateNodeData).toHaveBeenCalledWith("gal-1", {
-      images: ["data:image/png;base64,result", "old.png"],
-    });
+    expect(ctx.appendOutputGalleryImage).toHaveBeenCalledWith("gal-1", "data:image/png;base64,result");
   });
 });

src/store/execution/__tests__/simpleNodeExecutors.test.ts

@@ -34,6 +34,7 @@ function makeCtx(
     generationsPath: null,
     saveDirectoryPath: null,
     trackSaveGeneration: vi.fn(),
+    appendOutputGalleryImage: vi.fn(),
     get: vi.fn(),
     ...overrides,
   };

src/store/execution/__tests__/splitGridExecutor.test.ts

@@ -84,6 +84,7 @@ function makeCtx(
     generationsPath: null,
     saveDirectoryPath: null,
     trackSaveGeneration: vi.fn(),
+    appendOutputGalleryImage: vi.fn(),
     get: vi.fn(),
     ...overrides,
   };

src/store/execution/__tests__/videoProcessingExecutors.test.ts

@@ -48,6 +48,7 @@ function makeCtx(
     generationsPath: null,
     saveDirectoryPath: null,
     trackSaveGeneration: vi.fn(),
+    appendOutputGalleryImage: vi.fn(),
     get: vi.fn(),
     ...overrides,
   };

src/store/execution/nanoBananaExecutor.ts

@@ -7,7 +7,6 @@
 
 import type {
   NanoBananaNodeData,
-  OutputGalleryNodeData,
 } from "@/types";
 import { calculateGenerationCost } from "@/utils/costCalculator";
 import { buildGenerateHeaders } from "@/store/utils/buildApiHeaders";
@@ -35,6 +34,7 @@ export async function executeNanoBanana(
     addToGlobalHistory,
     generationsPath,
     trackSaveGeneration,
+    appendOutputGalleryImage,
     get,
   } = ctx;
 
@@ -150,7 +150,7 @@ export async function executeNanoBanana(
         selectedHistoryIndex: 0,
       });
 
-      // Push new image to connected downstream outputGallery nodes
+      // Push new image to connected downstream outputGallery nodes (atomic append)
       const edges = getEdges();
       const nodes = getNodes();
       edges
@@ -158,10 +158,7 @@ export async function executeNanoBanana(
         .forEach((e) => {
           const target = nodes.find((n) => n.id === e.target);
           if (target?.type === "outputGallery") {
-            const gData = target.data as OutputGalleryNodeData;
-            updateNodeData(target.id, {
-              images: [result.image, ...(gData.images || [])],
-            });
+            appendOutputGalleryImage(target.id, result.image);
           }
         });
 

src/store/execution/types.ts

@@ -46,6 +46,7 @@ export interface NodeExecutionContext {
   generationsPath: string | null;
   saveDirectoryPath: string | null;
   trackSaveGeneration: (key: string, promise: Promise<void>) => void;
+  appendOutputGalleryImage: (targetId: string, image: string) => void;
   get: () => unknown;
 }
 

src/store/workflowStore.ts

@@ -14,6 +14,7 @@ import {
   WorkflowEdge,
   NodeType,
   NanoBananaNodeData,
+  OutputGalleryNodeData,
   WorkflowNodeData,
   ImageHistoryItem,
   NodeGroup,
@@ -815,6 +816,16 @@ export const useWorkflowStore = create<WorkflowStore>((set, get) => ({
           pendingImageSyncs.set(key, promise);
           promise.finally(() => pendingImageSyncs.delete(key));
         },
+        appendOutputGalleryImage: (targetId: string, image: string) => {
+          set((state) => ({
+            nodes: state.nodes.map((n) =>
+              n.id === targetId && n.type === "outputGallery"
+                ? { ...n, data: { ...n.data, images: [image, ...((n.data as OutputGalleryNodeData).images || [])] } as WorkflowNodeData }
+                : n
+            ) as WorkflowNode[],
+            hasUnsavedChanges: true,
+          }));
+        },
         get: get as () => unknown,
       };
 
@@ -1022,6 +1033,16 @@ export const useWorkflowStore = create<WorkflowStore>((set, get) => ({
           pendingImageSyncs.set(key, promise);
           promise.finally(() => pendingImageSyncs.delete(key));
         },
+        appendOutputGalleryImage: (targetId: string, image: string) => {
+          set((state) => ({
+            nodes: state.nodes.map((n) =>
+              n.id === targetId && n.type === "outputGallery"
+                ? { ...n, data: { ...n.data, images: [image, ...((n.data as OutputGalleryNodeData).images || [])] } as WorkflowNodeData }
+                : n
+            ) as WorkflowNode[],
+            hasUnsavedChanges: true,
+          }));
+        },
         get: get as () => unknown,
       };