feat: Anti-Fake-Evidence System (Phase 1-4b)

Implement full evidence integrity pipeline to prevent compliance theater:
- Confidence levels (E0-E4), truth status tracking, assertion engine
- Four-Eyes approval workflow, audit trail, reject endpoint
- Evidence distribution dashboard, LLM audit routes
- Traceability matrix (backend endpoint + Compliance Hub UI tab)
- Anti-fake badges, control status machine, normative patterns
- 2 migrations, 4 test suites, MkDocs documentation

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

backend-compliance/tests/test_evidence_routes.py

@@ -56,6 +56,22 @@ def make_evidence(overrides=None):
     e.valid_until = None
     e.collected_at = NOW
     e.created_at = NOW
+    # Anti-Fake-Evidence fields
+    e.confidence_level = MagicMock()
+    e.confidence_level.value = "E1"
+    e.truth_status = MagicMock()
+    e.truth_status.value = "uploaded"
+    e.generation_mode = None
+    e.may_be_used_as_evidence = True
+    e.reviewed_by = None
+    e.reviewed_at = None
+    # Phase 2 fields
+    e.approval_status = "none"
+    e.first_reviewer = None
+    e.first_reviewed_at = None
+    e.second_reviewer = None
+    e.second_reviewed_at = None
+    e.requires_four_eyes = False
     if overrides:
         for k, v in overrides.items():
             setattr(e, k, v)