feat: add generation cancel job functionality and improve job handling

- Introduced `generationCancelJob` command ID in `commands/ids.ts`.
- Added `GenerationCancelJobPayload` type in `commands/payloads.ts`.
- Enhanced job status to include "cancelled" in `editor/state.ts`.
- Updated `runGenerationJob` to accept an `AbortSignal` and handle cancellation.
- Implemented cancellation logic in `runGenerate` and related functions.
- Added tests for job cancellation in `operations/generation/workflow.test.ts`.
- Improved layer rendering logic to prevent stack overflow in `editor/document-indexes.ts`.
- Added raster size assertions in `platform/browser/rasterLimits.ts` for image processing limits.
- Enhanced image file handling to check for size limits in `platform/browser/imageFiles.ts`.
- Updated UI components to reflect job cancellation state in `view/GenerationJobStatus.tsx` and `view/bottom-controls/GenerateActionControls.tsx`.

operations/generation/workflow.test.ts

@@ -39,6 +39,25 @@ describe("generation workflow", () => {
     expect(app.store.getState().document.artboards[0]?.layers.some((layer) => layer.id === "layer-new")).toBe(true);
     expect(app.store.getState().editor.generation.candidates).toHaveLength(0);
   });
+
+  test("cancels the active operation and records a cancelled job", async () => {
+    const app = createTestApp();
+    let receivedSignal: AbortSignal | undefined;
+    const workflow = createGenerationWorkflow(app.store, dependencies({
+      runGenerate: async (options) => {
+        receivedSignal = options.signal;
+        await new Promise<void>((_resolve, reject) => options.signal?.addEventListener("abort", () => reject(new DOMException("Cancelled", "AbortError")), { once: true }));
+      },
+    }));
+
+    const running = workflow.generate();
+    await Promise.resolve();
+    workflow.cancel();
+    await running;
+
+    expect(receivedSignal?.aborted).toBe(true);
+    expect(app.store.getState().editor.generation.jobs[0]?.status).toBe("cancelled");
+  });
 });
 
 function dependencies(overrides: Partial<GenerationWorkflowDependencies>): GenerationWorkflowDependencies {