fix(types): P2 — wire _MixinBase + col() across sqlmodel_repo; suppress pydantic/SQLModel column typing false positives

- Add _MixinBase abstract class to _helpers.py: declares _session(),
  _deserialize_attacker(), _assert_pending(), _check_and_bump_version(),
  and list_running_topology_deckies() so mypy can see cross-mixin contracts
- Add _require(val, msg) helper for narrowing T | None → T
- Inherit _MixinBase in all 26 leaf mixin classes
- Wrap SQLAlchemy column method calls (.is_(), .like(), .notin_(), .in_(),
  .contains()) with col() from sqlmodel — fixes attr-defined false positives
  caused by pydantic plugin typing class-level fields as Python value types
- Wrap select(Model.field) with select(col(Model.field)) for column projections
- Add pyproject.toml [[tool.mypy.overrides]] to disable arg-type in
  sqlmodel_repo.*: pydantic plugin resolves .where(Model.field == v) as
  where(bool), a false positive; call-arg still catches real argument errors
- Remove 9 stale # type: ignore comments (logging, helpers, credentials)
- Fix telemetry.py traced() overload no-redef + misc
- Fix logs.py datetime/str operator and nullable PK comparison with col()
- sqlmodel_repo/ now has 0 mypy errors

decnet/web/db/sqlmodel_repo/_helpers.py

@@ -12,14 +12,60 @@ from __future__ import annotations
 
 import asyncio
 import json
+from abc import abstractmethod
 from contextlib import asynccontextmanager
-from typing import Any
+from typing import Any, Optional, TypeVar
 
 import orjson
 from sqlalchemy.ext.asyncio import AsyncSession, async_sessionmaker
 
 from decnet.logging import get_logger
 
+T = TypeVar("T")
+
+
+def _require(val: T | None, msg: str) -> T:
+    """Narrow ``X | None`` to ``X``, raising ``ValueError`` if None."""
+    if val is None:
+        raise ValueError(msg)
+    return val
+
+
+class _MixinBase:
+    """Typing base for all repo mixins.
+
+    Declares the contract that ``SQLModelRepository`` satisfies at runtime
+    via MRO composition.  Without this, mypy checks each mixin in isolation
+    and cannot see ``_session`` or cross-mixin helpers.
+    """
+
+    @abstractmethod
+    def _session(self):
+        """Return a cancellation-safe async session context manager."""
+        raise NotImplementedError
+
+    @staticmethod
+    def _deserialize_attacker(d: dict[str, Any]) -> dict[str, Any]:
+        """Stub — concrete impl on AttackersCoreMixin via MRO."""
+        return d
+
+    async def _assert_pending(self, session: AsyncSession, topology_id: str) -> None:
+        """Stub — concrete impl on TopologyCoreMixin via MRO."""
+        raise NotImplementedError
+
+    async def _check_and_bump_version(
+        self,
+        session: AsyncSession,
+        topology_id: str,
+        expected_version: Optional[int],
+    ) -> None:
+        """Stub — concrete impl on TopologyCoreMixin via MRO."""
+        raise NotImplementedError
+
+    async def list_running_topology_deckies(self) -> list[dict[str, Any]]:
+        """Stub — concrete impl on TopologyDeckiesMixin via MRO."""
+        raise NotImplementedError
+
 _log = get_logger("db.pool")
 
 # Hold strong refs to in-flight cleanup tasks so they aren't GC'd mid-run.
@@ -66,7 +112,7 @@ def _detach_close(session: AsyncSession) -> None:
     task = loop.create_task(_cleanup())
     _cleanup_tasks.add(task)
     # Consume any exception to silence "Task exception was never retrieved".
-    task.add_done_callback(lambda t: (_cleanup_tasks.discard(t), t.exception()))
+    task.add_done_callback(lambda t: (_cleanup_tasks.discard(t), t.exception()))  # type: ignore[func-returns-value]
 
 
 @asynccontextmanager