fix(gate): clear the xenon complexity failure + fixable test warnings

- transcript_retention.py: split select_prunable_transcripts into small helpers
  so the module averages complexity rank A (was B — failed make quality / xenon).
- pyproject: move the markers table from [tool.coverage.run] (coverage warned
  'Unrecognized option') to [tool.pytest.ini_options] where it belongs.
- HTTP_422_UNPROCESSABLE_ENTITY -> HTTP_422_UNPROCESSABLE_CONTENT (old name
  deprecated) in the tasks/product/settings routes + the validation middleware.
- conftest: drop pool_pre_ping on the per-test engine — pointless for a fresh
  per-test engine and it leaves an un-awaited asyncpg Connection._cancel
  coroutine that surfaced as a RuntimeWarning across ~30 integration tests.

pyproject.toml

@@ -237,6 +237,12 @@ testpaths = ["tests"]
 python_files = ["test_*.py"]
 asyncio_default_fixture_loop_scope = "function"
 addopts = "--cov=roboco --cov-report=term-missing"
+markers = [
+    "asyncio: mark tests as async",
+    "slow: marks tests as slow",
+    "integration: marks tests as integration tests",
+    "unit: marks tests as unit tests",
+]
 
 [tool.coverage.run]
 # Coverage core. Python 3.12+ supports sys.monitoring; the legacy `pytrace`
@@ -286,12 +292,6 @@ omit = [
     # Auto-generated migrations.
     "alembic/*",
 ]
-markers = [
-    "asyncio: mark tests as async",
-    "slow: marks tests as slow",
-    "integration: marks tests as integration tests",
-    "unit: marks tests as unit tests",
-]
 
 # =============================================================================
 # Vulture Configuration

roboco/api/middleware.py

@@ -389,7 +389,7 @@ async def request_validation_handler(request: Request, exc: Exception) -> JSONRe
     if remediate is not None:
         content["remediate"] = remediate
     return JSONResponse(
-        status_code=http_status.HTTP_422_UNPROCESSABLE_ENTITY,
+        status_code=http_status.HTTP_422_UNPROCESSABLE_CONTENT,
         content=content,
     )
 

roboco/api/routes/product.py

@@ -74,7 +74,7 @@ async def create_product(
                 detail="Duplicate cell: each team may map to at most one project.",
             ) from e
         raise HTTPException(
-            status.HTTP_422_UNPROCESSABLE_ENTITY,
+            status.HTTP_422_UNPROCESSABLE_CONTENT,
             detail="Invalid cell mapping: project_id does not reference a project.",
         ) from e
     return product_to_response(product)
@@ -131,7 +131,7 @@ async def update_product(
                 detail="Duplicate cell: each team may map to at most one project.",
             ) from e
         raise HTTPException(
-            status.HTTP_422_UNPROCESSABLE_ENTITY,
+            status.HTTP_422_UNPROCESSABLE_CONTENT,
             detail="Invalid cell mapping: project_id does not reference a project.",
         ) from e
     return product_to_response(product)

roboco/api/routes/settings.py

@@ -30,7 +30,7 @@ async def update_setting(
         await service.set(key, data.value)
     except SettingValidationError as exc:
         raise HTTPException(
-            status_code=status.HTTP_422_UNPROCESSABLE_ENTITY, detail=str(exc)
+            status_code=status.HTTP_422_UNPROCESSABLE_CONTENT, detail=str(exc)
         ) from exc
     # Write route commits explicitly (get_db auto-commit is unreliable).
     await db.commit()

roboco/api/routes/tasks.py

@@ -154,7 +154,7 @@ async def create_task(
             agent_row = await get_agent_by_slug(db, data.assigned_to)
             if agent_row is None:
                 raise HTTPException(
-                    status_code=status.HTTP_422_UNPROCESSABLE_ENTITY,
+                    status_code=status.HTTP_422_UNPROCESSABLE_CONTENT,
                     detail={
                         "error": {
                             "code": "ASSIGNEE_NOT_FOUND",

roboco/runtime/transcript_retention.py

@@ -37,6 +37,19 @@ def is_agent_owned_dir(dir_name: str, workspaces_root: str) -> bool:
     return bool(encoded_root) and dir_name.startswith(encoded_root)
 
 
+def _is_old_transcript(path: Path, cutoff_epoch: float) -> bool:
+    """True if ``path`` is a regular .jsonl file last modified before the cutoff."""
+    try:
+        return path.is_file() and path.stat().st_mtime < cutoff_epoch
+    except OSError:
+        return False
+
+
+def _old_transcripts_in(directory: Path, cutoff_epoch: float) -> list[Path]:
+    """Old ``*.jsonl`` transcripts directly inside one agent-owned dir."""
+    return [t for t in directory.glob("*.jsonl") if _is_old_transcript(t, cutoff_epoch)]
+
+
 def select_prunable_transcripts(
     projects_root: Path, workspaces_root: str, cutoff_epoch: float
 ) -> list[Path]:
@@ -50,12 +63,6 @@ def select_prunable_transcripts(
         return []
     prunable: list[Path] = []
     for child in sorted(projects_root.iterdir()):
-        if not child.is_dir() or not is_agent_owned_dir(child.name, workspaces_root):
-            continue
-        for transcript in child.glob("*.jsonl"):
-            try:
-                if transcript.is_file() and transcript.stat().st_mtime < cutoff_epoch:
-                    prunable.append(transcript)
-            except OSError:
-                continue
+        if child.is_dir() and is_agent_owned_dir(child.name, workspaces_root):
+            prunable.extend(_old_transcripts_in(child, cutoff_epoch))
     return prunable

tests/conftest.py

@@ -214,7 +214,10 @@ async def db_session(_test_database_url: str) -> AsyncIterator[AsyncSession]:
     Each test gets its own session and connection; teardown rolls back any
     uncommitted state and disposes the engine to keep connection counts low.
     """
-    engine = create_async_engine(_test_database_url, future=True, pool_pre_ping=True)
+    # No pool_pre_ping: a fresh per-test engine can't have stale connections, and
+    # pre-ping on asyncpg leaves an un-awaited Connection._cancel coroutine that
+    # surfaces as a RuntimeWarning during GC.
+    engine = create_async_engine(_test_database_url, future=True)
     factory = async_sessionmaker(
         bind=engine, class_=AsyncSession, expire_on_commit=False
     )