fix: TTS/润色/标题/克隆 API 前置积分检查 + 402 异常透传

- voice.py: synthesize/synthesize-batch/synthesize-file/clone/submit 添加前置积分检查

- script.py: polish/generate_title 添加前置积分检查

- 修复 HTTPException(402) 被外层 except Exception 吞掉变成 500 的问题

- 所有端点在执行业务前先检查余额，不足直接返回 402

python-api/app/api/v1/script.py

@@ -67,6 +67,15 @@ async def polish_content(
     service = get_script_service()
     type_name = "画面" if request.polish_type == "scene" else "文案"
 
+    # 前置积分检查
+    required_points = ps._calculate_cost("polish")
+    check = await ps.check_balance(db, current_user.id, required_points)
+    if not check["sufficient"]:
+        raise HTTPException(
+            status_code=402,
+            detail=f"积分不足，需要 {required_points} 积分，当前余额 {check['balance']}",
+        )
+
     try:
         polished = await service.polish_content(
             content=request.content,
@@ -90,6 +99,8 @@ async def polish_content(
             data=polished,
             message=f"{type_name}润色完成",
         )
+    except HTTPException:
+        raise
     except ValueError as e:
         if "积分不足" in str(e):
             raise HTTPException(status_code=402, detail=str(e))
@@ -177,6 +188,15 @@ async def generate_title(
         usage_note=usage_note,
     )
 
+    # 前置积分检查
+    required_points = ps._calculate_cost("title")
+    check = await ps.check_balance(db, current_user.id, required_points)
+    if not check["sufficient"]:
+        raise HTTPException(
+            status_code=402,
+            detail=f"积分不足，需要 {required_points} 积分，当前余额 {check['balance']}",
+        )
+
     try:
         async with asyncio.timeout(15):
             result = await model_router.generate(
@@ -209,6 +229,8 @@ async def generate_title(
             data=GenerateTitleResponse(title=title),
             message="标题生成成功",
         )
+    except HTTPException:
+        raise
     except TimeoutError:
         logger.warning("[generate_title] 标题生成超时")
         raise HTTPException(status_code=500, detail="标题生成超时，请重试")