消除前端 legacy gpt-image-2 档位的重复字面量

- EDITOR_IMAGE_MODEL_MUD_POINT_CONFIG 提取 GPT_IMAGE_2_5_TIER_PRICES，gpt-image-2 与 gpt-image-2.5 复用同一份泥点档位
- EDITOR_IMAGE_DIMENSION_OPTIONS 提取 GPT_IMAGE_2_5_DIMENSION_OPTIONS，两个 key 复用同一份尺寸档位
- 修正注释：legacy key 是持久化值的防御性别名，生产读取会先经 normalizeEditorImageModel 归一，不再声称它被正式读路径按旧值使用

src/components/image-editor/ImageCanvasGenerationModel.ts

@@ -90,22 +90,22 @@ export const PUBLICATION_FRAME_DISPLAY_SIZE: Record<
   'publication-detail-gallery': { width: 360, height: 640 },
   'publication-promo-poster': { width: 560, height: 315 },
 };
+// `gpt-image-2` 仍是持久化在历史画布项里的模型值，配置保留为防御性别名；
+// 生产读取会先经过 normalizeEditorImageModel 归一，因此 legacy 档位必须与
+// `gpt-image-2.5` 同值，这里直接复用同一份常量避免两处字面量各自漂移。
+const GPT_IMAGE_2_5_TIER_PRICES = {
+  '1K': 3,
+  '2K': 5,
+} as const;
 export const EDITOR_IMAGE_MODEL_MUD_POINT_CONFIG = {
   [IMAGE_MODEL_NANOBANANA2]: {
     '0.5K': 8,
     '1K': 12,
     '2K': 24,
   },
-  [IMAGE_MODEL_GPT_IMAGE_2_5]: {
-    '1K': 3,
-    '2K': 5,
-  },
-  // Legacy persisted model value; keep readable for old assets without exposing
-  // it as a new selectable model.
-  [IMAGE_MODEL_GPT_IMAGE_2]: {
-    '1K': 3,
-    '2K': 5,
-  },
+  [IMAGE_MODEL_GPT_IMAGE_2_5]: GPT_IMAGE_2_5_TIER_PRICES,
+  // 历史持久化值；不作为新的可选模型暴露，只保证旧值可读。
+  [IMAGE_MODEL_GPT_IMAGE_2]: GPT_IMAGE_2_5_TIER_PRICES,
 } as const;
 export const SPEC_GENERATION_COST =
   EDITOR_IMAGE_MODEL_MUD_POINT_CONFIG[SPEC_GENERATION_MODEL][
@@ -139,19 +139,18 @@ export const EDITOR_IMAGE_MODEL_OPTIONS = [
   { label: 'GPT Image 2.5', value: IMAGE_MODEL_GPT_IMAGE_2_5 },
 ] as const;
 export const QUICK_EDIT_MODEL_OPTIONS = EDITOR_IMAGE_MODEL_OPTIONS;
+// 同上：legacy `gpt-image-2` 与 `gpt-image-2.5` 共用同一份尺寸档位常量。
+const GPT_IMAGE_2_5_DIMENSION_OPTIONS = {
+  aspectRatios: ['1:1', '4:3', '3:2', '2:3', '9:16', '16:9'],
+  imageSizes: ['1K', '2K'],
+} as const;
 export const EDITOR_IMAGE_DIMENSION_OPTIONS = {
   [IMAGE_MODEL_NANOBANANA2]: {
     aspectRatios: ['1:1', '4:3', '3:2', '2:3', '9:16', '16:9'],
     imageSizes: ['0.5K', '1K', '2K'],
   },
-  [IMAGE_MODEL_GPT_IMAGE_2_5]: {
-    aspectRatios: ['1:1', '4:3', '3:2', '2:3', '9:16', '16:9'],
-    imageSizes: ['1K', '2K'],
-  },
-  [IMAGE_MODEL_GPT_IMAGE_2]: {
-    aspectRatios: ['1:1', '4:3', '3:2', '2:3', '9:16', '16:9'],
-    imageSizes: ['1K', '2K'],
-  },
+  [IMAGE_MODEL_GPT_IMAGE_2_5]: GPT_IMAGE_2_5_DIMENSION_OPTIONS,
+  [IMAGE_MODEL_GPT_IMAGE_2]: GPT_IMAGE_2_5_DIMENSION_OPTIONS,
 } as const;
 
 type EditorImageFrameSize = {