fix:优化工作面板，支持动态字数

app/schemas.py

@@ -11,6 +11,12 @@ class RewriteRequest(BaseModel):
     audience: str = "公众号读者"
     keep_points: str = ""
     avoid_words: str = ""
+    target_body_chars: int = Field(
+        default=500,
+        ge=180,
+        le=2200,
+        description="目标改写正文字数，前端可调（中文字符数近似）",
+    )
 
 
 class RewriteResponse(BaseModel):