fix(api): use proper Annotated pattern in audit_logs.py, remove experimental root test files

- Remove _db_dep singleton and its use as default value in function signatures
- Use DbSession = Annotated[Session, Depends(get_db)] directly (matches files.py pattern)
- Declare db: DbSession without a default (FastAPI DI provides the session)
- Delete 10 experimental test_*.py files left at repo root from B008 debugging

Co-authored-by: christianlouis <361235+christianlouis@users.noreply.github.com>

app/api/audit_logs.py

@@ -20,16 +20,14 @@ logger = logging.getLogger(__name__)
 
 router = APIRouter()
 
-# Module-level dependency singleton to satisfy Ruff B008 while maintaining default values for manual calls (e.g. in decorators).
-_db_dep = Depends(get_db)
-DbSession = Annotated[Session, _db_dep]
+DbSession = Annotated[Session, Depends(get_db)]
 
 
 @router.get("/audit-logs")
 @require_login
 async def list_audit_logs(
     request: Request,
-    db: DbSession = _db_dep,
+    db: DbSession,
     action: Annotated[str | None, Query(description="Filter by action (exact match)")] = None,
     user: Annotated[str | None, Query(description="Filter by username")] = None,
     resource_type: Annotated[str | None, Query(description="Filter by resource type")] = None,
@@ -75,7 +73,7 @@ async def list_audit_logs(
 @require_login
 async def list_distinct_actions(
     request: Request,
-    db: DbSession = _db_dep,
+    db: DbSession,
 ) -> list[str]:
     """Return the distinct action values present in the audit log."""
     from app.models import AuditLog
@@ -88,7 +86,7 @@ async def list_distinct_actions(
 @require_login
 async def list_distinct_users(
     request: Request,
-    db: DbSession = _db_dep,
+    db: DbSession,
 ) -> list[str]:
     """Return the distinct user values present in the audit log."""
     from app.models import AuditLog