refactor(persistence): organize entities into per-entity directories

Restructure the persistence layer from horizontal "models/ + repositories/"
split into vertical entity-aligned directories. Each entity (thread_meta,
run, feedback) now owns its ORM model, abstract interface (where applicable),
and concrete implementations under a single directory with an aggregating
__init__.py for one-line imports.

Layout:
  persistence/thread_meta/{base,model,sql,memory}.py
  persistence/run/{model,sql}.py
  persistence/feedback/{model,sql}.py

models/__init__.py is kept as a facade so Alembic autogenerate continues to
discover all ORM tables via Base.metadata. RunEventRow remains under
models/run_event.py because its storage implementation lives in
runtime/events/store/db.py and has no matching repository directory.

The repositories/ directory is removed entirely. All call sites in
gateway/deps.py and tests are updated to import from the new entity
packages, e.g.:

    from deerflow.persistence.thread_meta import ThreadMetaRepository
    from deerflow.persistence.run import RunRepository
    from deerflow.persistence.feedback import FeedbackRepository

Full test suite passes (1690 passed, 14 skipped).

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

backend/packages/harness/deerflow/persistence/feedback/sql.py

@@ -0,0 +1,98 @@
+"""SQLAlchemy-backed feedback storage.
+
+Each method acquires its own short-lived session.
+"""
+
+from __future__ import annotations
+
+import uuid
+from datetime import UTC, datetime
+
+from sqlalchemy import case, func, select
+from sqlalchemy.ext.asyncio import AsyncSession, async_sessionmaker
+
+from deerflow.persistence.feedback.model import FeedbackRow
+
+
+class FeedbackRepository:
+    def __init__(self, session_factory: async_sessionmaker[AsyncSession]) -> None:
+        self._sf = session_factory
+
+    @staticmethod
+    def _row_to_dict(row: FeedbackRow) -> dict:
+        d = row.to_dict()
+        val = d.get("created_at")
+        if isinstance(val, datetime):
+            d["created_at"] = val.isoformat()
+        return d
+
+    async def create(
+        self,
+        *,
+        run_id: str,
+        thread_id: str,
+        rating: int,
+        owner_id: str | None = None,
+        message_id: str | None = None,
+        comment: str | None = None,
+    ) -> dict:
+        """Create a feedback record. rating must be +1 or -1."""
+        if rating not in (1, -1):
+            raise ValueError(f"rating must be +1 or -1, got {rating}")
+        row = FeedbackRow(
+            feedback_id=str(uuid.uuid4()),
+            run_id=run_id,
+            thread_id=thread_id,
+            owner_id=owner_id,
+            message_id=message_id,
+            rating=rating,
+            comment=comment,
+            created_at=datetime.now(UTC),
+        )
+        async with self._sf() as session:
+            session.add(row)
+            await session.commit()
+            await session.refresh(row)
+            return self._row_to_dict(row)
+
+    async def get(self, feedback_id: str) -> dict | None:
+        async with self._sf() as session:
+            row = await session.get(FeedbackRow, feedback_id)
+            return self._row_to_dict(row) if row else None
+
+    async def list_by_run(self, thread_id: str, run_id: str, *, limit: int = 100) -> list[dict]:
+        stmt = select(FeedbackRow).where(FeedbackRow.thread_id == thread_id, FeedbackRow.run_id == run_id).order_by(FeedbackRow.created_at.asc()).limit(limit)
+        async with self._sf() as session:
+            result = await session.execute(stmt)
+            return [self._row_to_dict(r) for r in result.scalars()]
+
+    async def list_by_thread(self, thread_id: str, *, limit: int = 100) -> list[dict]:
+        stmt = select(FeedbackRow).where(FeedbackRow.thread_id == thread_id).order_by(FeedbackRow.created_at.asc()).limit(limit)
+        async with self._sf() as session:
+            result = await session.execute(stmt)
+            return [self._row_to_dict(r) for r in result.scalars()]
+
+    async def delete(self, feedback_id: str) -> bool:
+        async with self._sf() as session:
+            row = await session.get(FeedbackRow, feedback_id)
+            if row is None:
+                return False
+            await session.delete(row)
+            await session.commit()
+            return True
+
+    async def aggregate_by_run(self, thread_id: str, run_id: str) -> dict:
+        """Aggregate feedback stats for a run using database-side counting."""
+        stmt = select(
+            func.count().label("total"),
+            func.coalesce(func.sum(case((FeedbackRow.rating == 1, 1), else_=0)), 0).label("positive"),
+            func.coalesce(func.sum(case((FeedbackRow.rating == -1, 1), else_=0)), 0).label("negative"),
+        ).where(FeedbackRow.thread_id == thread_id, FeedbackRow.run_id == run_id)
+        async with self._sf() as session:
+            row = (await session.execute(stmt)).one()
+            return {
+                "run_id": run_id,
+                "total": row.total,
+                "positive": row.positive,
+                "negative": row.negative,
+            }