chore(backend): deprecation sweep — Pydantic V1 -> V2, utcnow -> tz-aware

Two low-risk Pydantic V1 idioms that will be hard errors in V3:
  - Query(regex=...) -> Query(pattern=...) (audit_routes, control_generator_routes)
  - class Config: from_attributes=True -> model_config = ConfigDict(...)
    in source_policy_router.py (schemas.py is intentionally skipped — it is
    the Phase 1 schema-split target and the ConfigDict conversion is most
    efficient to do during that split).

Naive -> aware datetime sweep across 47 files:
  - datetime.utcnow() -> datetime.now(timezone.utc)
  - default=datetime.utcnow -> default=lambda: datetime.now(timezone.utc)
  - onupdate=datetime.utcnow -> onupdate=lambda: datetime.now(timezone.utc)

All SQLAlchemy DateTime columns in the project already declare
timezone=True, so the DB schema expects aware datetimes. Before this
commit, the in-Python side was generating naive values and the driver
was silently coercing them. This is a latent-bug fix, not a behavior
change at the DB boundary.

Verified:
  - 173/173 pytest compliance/tests/ pass (same as baseline)
  - tests/contracts/test_openapi_baseline.py passes (360 paths,
    484 operations unchanged)
  - DeprecationWarning count dropped from 158 -> 35

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

backend-compliance/compliance/tests/test_isms_routes.py

@@ -15,7 +15,7 @@ Run with: pytest backend/compliance/tests/test_isms_routes.py -v
 """
 
 import pytest
-from datetime import datetime, date
+from datetime import datetime, date, timezone
 from unittest.mock import MagicMock
 from uuid import uuid4
 
@@ -56,7 +56,7 @@ def sample_scope():
         status=ApprovalStatusEnum.DRAFT,
         version="1.0",
         created_by="admin@breakpilot.de",
-        created_at=datetime.utcnow(),
+        created_at=datetime.now(timezone.utc),
     )
 
 
@@ -65,7 +65,7 @@ def sample_approved_scope(sample_scope):
     """Create an approved ISMS scope for testing."""
     sample_scope.status = ApprovalStatusEnum.APPROVED
     sample_scope.approved_by = "ceo@breakpilot.de"
-    sample_scope.approved_at = datetime.utcnow()
+    sample_scope.approved_at = datetime.now(timezone.utc)
     sample_scope.effective_date = date.today()
     sample_scope.review_date = date(date.today().year + 1, date.today().month, date.today().day)
     sample_scope.approval_signature = "sha256_signature_hash"
@@ -88,7 +88,7 @@ def sample_policy():
         authored_by="iso@breakpilot.de",
         status=ApprovalStatusEnum.DRAFT,
         version="1.0",
-        created_at=datetime.utcnow(),
+        created_at=datetime.now(timezone.utc),
     )
 
 
@@ -116,7 +116,7 @@ def sample_objective():
         related_controls=["OPS-003"],
         status="active",
         progress_percentage=0.0,
-        created_at=datetime.utcnow(),
+        created_at=datetime.now(timezone.utc),
     )
 
 
@@ -136,7 +136,7 @@ def sample_soa_entry():
         coverage_level="full",
         evidence_description="ISMS Policy v2.0, signed by CEO",
         version="1.0",
-        created_at=datetime.utcnow(),
+        created_at=datetime.now(timezone.utc),
     )
 
 
@@ -158,7 +158,7 @@ def sample_finding():
         identified_date=date.today(),
         due_date=date(2026, 3, 31),
         status=FindingStatusEnum.OPEN,
-        created_at=datetime.utcnow(),
+        created_at=datetime.now(timezone.utc),
     )
 
 
@@ -178,7 +178,7 @@ def sample_major_finding():
         identified_date=date.today(),
         due_date=date(2026, 2, 28),
         status=FindingStatusEnum.OPEN,
-        created_at=datetime.utcnow(),
+        created_at=datetime.now(timezone.utc),
     )
 
 
@@ -198,7 +198,7 @@ def sample_capa(sample_finding):
         planned_completion=date(2026, 2, 15),
         effectiveness_criteria="Document approved and distributed to audit team",
         status="planned",
-        created_at=datetime.utcnow(),
+        created_at=datetime.now(timezone.utc),
     )
 
 
@@ -219,7 +219,7 @@ def sample_management_review():
             {"name": "ISO", "role": "ISMS Manager"},
         ],
         status="draft",
-        created_at=datetime.utcnow(),
+        created_at=datetime.now(timezone.utc),
     )
 
 
@@ -239,7 +239,7 @@ def sample_internal_audit():
         lead_auditor="internal.auditor@breakpilot.de",
         audit_team=["internal.auditor@breakpilot.de", "qa@breakpilot.de"],
         status="planned",
-        created_at=datetime.utcnow(),
+        created_at=datetime.now(timezone.utc),
     )
 
 
@@ -502,7 +502,7 @@ class TestISMSReadinessCheck:
         """Readiness check should identify potential major findings."""
         check = ISMSReadinessCheckDB(
             id=str(uuid4()),
-            check_date=datetime.utcnow(),
+            check_date=datetime.now(timezone.utc),
             triggered_by="admin@breakpilot.de",
             overall_status="not_ready",
             certification_possible=False,
@@ -532,7 +532,7 @@ class TestISMSReadinessCheck:
         """Readiness check should show status for each ISO chapter."""
         check = ISMSReadinessCheckDB(
             id=str(uuid4()),
-            check_date=datetime.utcnow(),
+            check_date=datetime.now(timezone.utc),
             triggered_by="admin@breakpilot.de",
             overall_status="ready",
             certification_possible=True,
@@ -606,7 +606,7 @@ class TestAuditTrail:
             entity_name="ISMS Scope v1.0",
             action="approve",
             performed_by="ceo@breakpilot.de",
-            performed_at=datetime.utcnow(),
+            performed_at=datetime.now(timezone.utc),
             checksum="sha256_hash",
         )
 
@@ -630,7 +630,7 @@ class TestAuditTrail:
             new_value="approved",
             change_summary="Policy approved by CEO",
             performed_by="ceo@breakpilot.de",
-            performed_at=datetime.utcnow(),
+            performed_at=datetime.now(timezone.utc),
             checksum="sha256_hash",
         )