feature：新增章节内容-局部重写功能，支持扩展内容

frontend/src/services/api.ts

@@ -616,6 +616,45 @@ export const chapterApi = {
         completed_at: string | null;
       }>;
     }>(`/chapters/${chapterId}/regeneration/tasks`, { params: { limit } }),
+
+  // 局部重写相关
+  partialRegenerateStream: (
+    chapterId: string,
+    data: {
+      selected_text: string;
+      start_position: number;
+      end_position: number;
+      user_instructions: string;
+      context_chars?: number;
+      style_id?: number;
+      length_mode?: 'similar' | 'expand' | 'condense' | 'custom';
+      target_word_count?: number;
+    },
+    options?: SSEClientOptions
+  ) => ssePost<{
+    new_text: string;
+    word_count: number;
+    original_word_count: number;
+    start_position: number;
+    end_position: number;
+  }>(
+    `/api/chapters/${chapterId}/partial-regenerate-stream`,
+    data,
+    options
+  ),
+
+  applyPartialRegenerate: (chapterId: string, data: {
+    new_text: string;
+    start_position: number;
+    end_position: number;
+  }) =>
+    api.post<unknown, {
+      success: boolean;
+      chapter_id: string;
+      word_count: number;
+      old_word_count: number;
+      message: string;
+    }>(`/chapters/${chapterId}/apply-partial-regenerate`, data),
 };
 
 export const writingStyleApi = {