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.

view/canvas/renderFrame.test.ts

@@ -151,6 +151,36 @@ const visualEditorChanges: Array<[string, (state: AppState) => AppState]> = [
       },
     }),
   ],
+  [
+    "generation candidate preview",
+    (state) => ({
+      ...state,
+      editor: {
+        ...state.editor,
+        generation: {
+          candidates: [
+            {
+              id: "candidate",
+              source: "data:image/png;base64,candidate",
+              mimeType: "image/png",
+              intrinsicSize: { w: 64, h: 64 },
+              mode: "text-to-image",
+              settings: state.editor.tools.generate,
+              seed: 12,
+              width: 64,
+              height: 64,
+              placement: {
+                artboardId: "artboard",
+                layerName: "Candidate",
+                transform: { position: { x: 1, y: 2 }, scale: { x: 1, y: 1 }, rotation: 0 },
+              },
+            },
+          ],
+          selectedCandidateId: "candidate",
+        },
+      },
+    }),
+  ],
   [
     "active tool",
     (state) => ({