refactor(types): add comprehensive type annotations across backend Python codebase

Enable ANN rules in ruff.toml (flake8-annotations) and resolve all 221 violations:

ANN201/ANN202 — return types on 168 public/private functions:
- All 28 FastAPI routers: endpoints annotated with dict/list/specific schema/
  StreamingResponse/FileResponse/JSONResponse as appropriate
- main.py: lifespan→AsyncGenerator[None,None], exception handlers→JSONResponse
- database.py: get_db→Generator[Session,None,None], proxy methods→correct types
- middleware/request_context.py: dispatch→Response with Callable call_next type

ANN001/ANN002/ANN003 — 32 missing argument types:
- seed_demo.py: all db parameters typed as Session
- domain/unit_of_work.py: __aexit__ exc_type/exc_val/exc_tb typed with TracebackType
- services: audit_service user_id→UUID|None, heatmap_service query/model/builder,
  notification_service test→Test, tempo_service test→Test/user→User,
  test_workflow_service test_id→UUID, campaign_crud **fields→object,
  test_crud **fields→object (4 sites)

ANN401 — 16 Any usages resolved:
- Domain entities (campaign/technique/threat_actor/test_entity): replaced Any with
  actual ORM types via TYPE_CHECKING guards to avoid circular imports
- detection_rule_service: test_id/detection_rule_id/evaluator_id→UUID
- score_cache: kept Any with # noqa: ANN401 (genuinely generic cache)
- jira_service/tempo_service: kept Any with # noqa: ANN401 (lazy optional deps)
- d3fend_import_service: _to_str(v: Any) kept with # noqa: ANN401

ANN204/ANN205/ANN206 — special/static/class methods:
- database.py proxy __call__/__getattr__: *args: object/**kwargs: object
- schemas/test.py model_validate: obj→object, **kwargs→object
- sa_technique_repository._int_type→type

All 439 unit tests pass. ruff check app/ → All checks passed!

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

backend/app/services/tempo_service.py

@@ -1,18 +1,20 @@
 """Tempo time-tracking integration service."""
 
 import logging
-from typing import Optional
+from typing import Any, Optional
 
 from sqlalchemy.orm import Session
 
 from app.config import settings
 from app.domain.exceptions import InvalidOperationError
 from app.models.jira_link import JiraLink, JiraLinkEntityType
+from app.models.test import Test
+from app.models.user import User
 
 logger = logging.getLogger(__name__)
 
 
-def get_tempo_client():
+def get_tempo_client() -> Any:  # noqa: ANN401  # tempoapiclient.Tempo imported lazily from optional dep
     """Return a Tempo API client, or raise if disabled."""
     if not settings.TEMPO_ENABLED:
         raise InvalidOperationError("Tempo integration is not enabled")
@@ -52,8 +54,8 @@ def log_worklog(
 
 def auto_log_test_worklog(
     db: Session,
-    test,
-    user,
+    test: Test,
+    user: User,
     activity_type: str,
 ) -> Optional[dict]:
     """If the test has a Jira link, log time to Tempo automatically.
@@ -97,7 +99,7 @@ def auto_log_test_worklog(
         return None
 
 
-def _calculate_duration(test, activity_type: str) -> int:
+def _calculate_duration(test: Test, activity_type: str) -> int:
     """Calculate real duration in seconds from the phase timing fields.
 
     Uses the actual start/end timestamps recorded by the workflow buttons,