feat: Add inpainting (局部重绘) feature for timeline editor

- Add canvas-based mask drawing tools (brush, eraser, rect, lasso)
- Add undo/redo history support for mask editing
- Integrate inpainting UI into preview player
- Add backend API endpoint for inpainting requests
- Add MediaService.inpaint method with ComfyUI workflow support
- Add Flux inpainting workflows for selfhost and RunningHub

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

workflows/selfhost/image_inpaint_flux.json

@@ -0,0 +1,149 @@
+{
+  "10": {
+    "inputs": {
+      "image": ""
+    },
+    "class_type": "LoadImage",
+    "_meta": {
+      "title": "$image.value!"
+    }
+  },
+  "11": {
+    "inputs": {
+      "image": "",
+      "channel": "alpha"
+    },
+    "class_type": "LoadImageMask",
+    "_meta": {
+      "title": "$mask.value!"
+    }
+  },
+  "12": {
+    "inputs": {
+      "grow_mask_by": 6,
+      "pixels": ["10", 0],
+      "vae": ["49", 0],
+      "mask": ["11", 0]
+    },
+    "class_type": "VAEEncodeForInpaint",
+    "_meta": {
+      "title": "VAE Encode (for Inpainting)"
+    }
+  },
+  "29": {
+    "inputs": {
+      "seed": 1067822190154760,
+      "steps": 20,
+      "cfg": 1,
+      "sampler_name": "euler",
+      "scheduler": "simple",
+      "denoise": 0.8,
+      "model": ["48", 0],
+      "positive": ["35", 0],
+      "negative": ["33", 0],
+      "latent_image": ["12", 0]
+    },
+    "class_type": "KSampler",
+    "_meta": {
+      "title": "KSampler"
+    }
+  },
+  "30": {
+    "inputs": {
+      "value": 0.8
+    },
+    "class_type": "easy float",
+    "_meta": {
+      "title": "$denoise.value"
+    }
+  },
+  "31": {
+    "inputs": {
+      "text": ["46", 0],
+      "clip": ["47", 0]
+    },
+    "class_type": "CLIPTextEncode",
+    "_meta": {
+      "title": "CLIP Text Encode (Prompt)"
+    }
+  },
+  "33": {
+    "inputs": {
+      "conditioning": ["31", 0]
+    },
+    "class_type": "ConditioningZeroOut",
+    "_meta": {
+      "title": "ConditioningZeroOut"
+    }
+  },
+  "35": {
+    "inputs": {
+      "guidance": 3.5,
+      "conditioning": ["31", 0]
+    },
+    "class_type": "FluxGuidance",
+    "_meta": {
+      "title": "FluxGuidance"
+    }
+  },
+  "36": {
+    "inputs": {
+      "filename_prefix": "inpaint",
+      "images": ["37", 0]
+    },
+    "class_type": "SaveImage",
+    "_meta": {
+      "title": "Save Image"
+    }
+  },
+  "37": {
+    "inputs": {
+      "samples": ["29", 0],
+      "vae": ["49", 0]
+    },
+    "class_type": "VAEDecode",
+    "_meta": {
+      "title": "VAE Decode"
+    }
+  },
+  "46": {
+    "inputs": {
+      "value": "inpaint region"
+    },
+    "class_type": "PrimitiveStringMultiline",
+    "_meta": {
+      "title": "$prompt.value!"
+    }
+  },
+  "47": {
+    "inputs": {
+      "clip_name1": "clip_l.safetensors",
+      "clip_name2": "t5xxl_fp8_e4m3fn.safetensors",
+      "type": "flux",
+      "device": "default"
+    },
+    "class_type": "DualCLIPLoader",
+    "_meta": {
+      "title": "DualCLIPLoader"
+    }
+  },
+  "48": {
+    "inputs": {
+      "unet_name": "flux1-dev.safetensors",
+      "weight_dtype": "default"
+    },
+    "class_type": "UNETLoader",
+    "_meta": {
+      "title": "Load Diffusion Model"
+    }
+  },
+  "49": {
+    "inputs": {
+      "vae_name": "ae.safetensors"
+    },
+    "class_type": "VAELoader",
+    "_meta": {
+      "title": "Load VAE"
+    }
+  }
+}