feat: implement inpainting functionality with mask handling

- Added `createMaskedPixelReplacementSource` function to handle pixel replacement using inpainting.
- Introduced `buildInpaintBundle` to prepare inpainting data including mask generation and validation.
- Created utility functions for mask operations such as `applyMaskedContentModeToRgba`, `expandRectWithinBounds`, and others for mask manipulation.
- Developed tests for inpainting preparation and mask raster utilities to ensure functionality and correctness.
- Implemented mask raster operations including inversion, feathering, blurring, and more.

app/comfy.test.ts

@@ -0,0 +1,59 @@
+import { describe, expect, test } from "bun:test";
+import { buildSdxlWorkflow, selectGeneratedOutputImage } from "./comfy";
+
+describe("Comfy adapter", () => {
+  test("selects SaveImage output instead of uploaded input or mask images", () => {
+    const image = selectGeneratedOutputImage({
+      outputs: {
+        "4": { images: [{ filename: "image-studio-input.png", type: "input" }] },
+        "9": { images: [{ filename: "image-studio-mask.png", type: "input" }] },
+        "8": { images: [{ filename: "image-studio-inpaint_00001_.png", subfolder: "", type: "output" }] },
+      },
+    });
+
+    expect(image).toEqual({ filename: "image-studio-inpaint_00001_.png", subfolder: "", type: "output" });
+  });
+
+  test("falls back to generated filename prefixes when node ids differ", () => {
+    const image = selectGeneratedOutputImage({
+      outputs: {
+        "12": { images: [{ filename: "image-studio-inpaint_00002_.png", type: "output" }] },
+        "4": { images: [{ filename: "image-studio-input.png", type: "input" }] },
+      },
+    });
+
+    expect(image?.filename).toBe("image-studio-inpaint_00002_.png");
+  });
+
+  test("builds neutral inpaint with VAEEncodeForInpaint", () => {
+    const workflow = buildSdxlWorkflow(inpaintRequest({ maskedContent: "neutral" }));
+
+    expect(workflow["5"]?.class_type).toBe("VAEEncodeForInpaint");
+    expect(workflow["5"]?.inputs).toMatchObject({ grow_mask_by: 6, mask: ["11", 0] });
+    expect(workflow["6"]?.inputs.latent_image).toEqual(["5", 0]);
+  });
+
+  test("builds original-content inpaint with a latent noise mask", () => {
+    const workflow = buildSdxlWorkflow(inpaintRequest({ maskedContent: "original", growMaskBy: 12 }));
+
+    expect(workflow["5"]?.class_type).toBe("VAEEncode");
+    expect(workflow["12"]?.class_type).toBe("GrowMask");
+    expect(workflow["12"]?.inputs).toMatchObject({ mask: ["11", 0], expand: 12 });
+    expect(workflow["13"]?.class_type).toBe("SetLatentNoiseMask");
+    expect(workflow["13"]?.inputs).toMatchObject({ samples: ["5", 0], mask: ["12", 0] });
+    expect(workflow["6"]?.inputs.latent_image).toEqual(["13", 0]);
+  });
+});
+
+function inpaintRequest(inpaint: { maskedContent: "neutral" | "original"; growMaskBy?: number }) {
+  return {
+    mode: "inpaint" as const,
+    model: "model.safetensors",
+    prompt: "replace garment",
+    width: 128,
+    height: 128,
+    inputImage: "input.png",
+    maskImage: "mask.png",
+    inpaint,
+  };
+}