feat(D1): 改稿进飞轮 - 最强真实信号 text_edit +5

倩倩姐2026-06-16拍板:改稿=用户真改了字=最在乎这条方向=最强真实信号。
先激进入飞轮跑一周,北哥用后按真实数据校准是否加"过审才入"闸门。

改动:
- enums.py: SignalType.TEXT_EDIT + SIGNAL_WEIGHTS权重5(≥选择类)
- task.py: TextCandidate.edited 布尔字段
- 013迁移: text_candidates加edited列 + preference_events.signal_type
  ENUM补text_edit(端到端实测抓出:不补会Data truncated)
- task_actions.py: POST /{task_id}/text-candidates/{cid}/edit 端点
  回写content+edited=True+record_signal写text_edit,走task_actions不碰review.py

端到端实测:edited False→True,飞轮信号真落库type=text_edit weight=5。
顺手: tsconfig.tsbuildinfo 移出版本控制(构建产物)。

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

backend/app/constants/enums.py

@@ -60,6 +60,7 @@ class SignalType(str, Enum):
     APPROVE = "approve"
     REJECT_WITH_REASON = "reject_with_reason"
     REGENERATE = "regenerate"
+    TEXT_EDIT = "text_edit"  # 改稿:用户真改了字=最强真实信号(倩倩姐2026-06-16拍板)
 
 
 # ── 飞轮信号权重默认值（北哥可校准）─────────────────────
@@ -69,6 +70,7 @@ SIGNAL_WEIGHTS: dict[str, int] = {
     SignalType.APPROVE: 5,
     SignalType.REJECT_WITH_REASON: -3,
     SignalType.REGENERATE: -1,
+    SignalType.TEXT_EDIT: 5,  # 最强信号,≥选择类(倩倩姐2026-06-16拍板;先激进跑一周再校准)
 }