M2b：删除旧 chat 体系——线性会话/叩心/情绪/纪念日模型与页面退役（迁移 003 双向验证），runs 去会话外键，测试全量修剪

backend/app/repositories/runtime.py

@@ -14,17 +14,14 @@ async def list_runs(
     session: AsyncSession,
     *,
     character_id: str | None = None,
-    session_id: str | None = None,
     status: str | None = None,
     page: int = 1,
     page_size: int = 20,
 ) -> tuple[list[Run], int]:
-    """按创建时间倒序分页返回 Run；可选按人物/会话/状态过滤，返回 (条目, 总数)。"""
+    """按创建时间倒序分页返回 Run；可选按人物/状态过滤，返回 (条目, 总数)。"""
     conds = []
     if character_id is not None:
         conds.append(Run.character_id == character_id)
-    if session_id is not None:
-        conds.append(Run.session_id == session_id)
     if status is not None:
         conds.append(Run.status == status)
     count_stmt = select(func.count()).select_from(Run)
@@ -127,11 +124,3 @@ async def summarize_by_trace(session: AsyncSession):
     return [(row[0], int(row[1]), row[2]) for row in result.all()]
 
 
-async def list_session_ids_by_runs(session: AsyncSession, run_ids: list[str]) -> list[str]:
-    """按 run_id 集合查询关联的 chat session_id 去重列表（链路追踪：run → 对话）。"""
-    if not run_ids:
-        return []
-    result = await session.execute(
-        select(Run.session_id).where(Run.id.in_(run_ids), Run.session_id.is_not(None))
-    )
-    return sorted({row[0] for row in result.all() if row[0]})