fix(render): 画中画模式全面下线 + 标题ASS自动换行

Q1 — 画中画(PiP)下线：
- worker: _build_plan_and_clips_from_task 移除pip/voice_pip分支，
  入口处强制映射为one_take（顺序拼接）
- api preview: _resolve_strategy_id_from_template 返回前做pip→one_take映射
- api generation_tasks: strategy_id中的pip/voice_pip统一映射为one_take
- 更新集成测试：pip/voice_pip测试改为验证one_take行为

Q2 — 标题自动换行：
- packages/domain/ass_subtitle_builder.py: 新增_wrap_title_text函数
  根据视频宽度、字号、边距估算每行最大字符数，CJK全角+英文半角
  超出可用宽度时插入\N硬换行
- build_ass_content中title Dialogue生成前调用自动换行

测试：75个ASS单测全绿 + 10个四模式测试全绿

apps/api/app/api/routes/generation_preview.py

@@ -125,6 +125,10 @@ def _resolve_strategy_id_from_template(
                     mode,
                     template_id,
                 )
+                # 画中画已下线，pip/voice_pip 统一映射为 one_take
+                if mode in ("pip", "voice_pip"):
+                    logger.info("[预览生成] %s → one_take (画中画已下线)", mode)
+                    mode = "one_take"
                 return mode
     except Exception:
         logger.debug(
@@ -146,6 +150,10 @@ def _resolve_strategy_id_from_template(
                     mode,
                     template_id,
                 )
+                # 画中画已下线，pip/voice_pip 统一映射为 one_take
+                if mode in ("pip", "voice_pip"):
+                    logger.info("[预览生成] %s → one_take (画中画已下线)", mode)
+                    mode = "one_take"
                 return mode
     except Exception:
         logger.warning(

apps/api/app/api/routes/generation_tasks.py

@@ -271,13 +271,19 @@ def create_generation_task(
             detail="系统繁忙，请稍后再试",
         ) from e
 
+    # 画中画已下线：strategy_id 中的 pip/voice_pip 统一映射为 one_take
+    effective_strategy_id = request.strategy_id
+    if effective_strategy_id in ("pip", "voice_pip"):
+        logger.info("画中画已下线，strategy_id %s → one_take", effective_strategy_id)
+        effective_strategy_id = "one_take"
+
     try:
         for _ in range(count):
             task = use_case.execute(
                 CreateGenerationTaskCommand(
                     project_id=project_id,
                     asset_library_id=asset_library_id,
-                    strategy_id=request.strategy_id,
+                    strategy_id=effective_strategy_id,
                     voice_library_id=request.voice_library_id,
                     template_id=request.template_id,
                     asset_ids=resolved_asset_ids,