feat(tests): disputed state + fix timestamps on reopen

1. New 'disputed' state — one lead approved, the other rejected:
   - Both approved → validated (unchanged)
   - Both rejected → rejected (unchanged)
   - One approves + one rejects → disputed (new)
   - DB: ALTER TYPE teststate ADD VALUE 'disputed'
   - Notification sent to the approving lead explaining the conflict
     with the rejection notes

2. Disputed UI in TestDetailHeader:
   - Amber banner showing conflict + rejection reason from notes
   - 'Change Vote to Rejected' button for the lead who approved
   - Validation indicators shown for disputed state too

3. Fix timestamps on reopen (rejected → draft):
   - Keep red_started_at, blue_started_at etc. as historical record
   - Only clear paused_at defensively
   - Timestamps naturally update when test is re-executed

4. disputed badge (amber) added to all badge color maps

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

backend/app/services/test_workflow_service.py

@@ -37,7 +37,8 @@ VALID_TRANSITIONS: dict[TestState, list[TestState]] = {
     TestState.draft:           [TestState.red_executing],
     TestState.red_executing:   [TestState.blue_evaluating],
     TestState.blue_evaluating: [TestState.in_review],
-    TestState.in_review:       [TestState.validated, TestState.rejected],
+    TestState.in_review:       [TestState.validated, TestState.rejected, TestState.disputed],
+    TestState.disputed:        [TestState.validated, TestState.rejected],
     TestState.rejected:        [TestState.draft],
     TestState.validated:       [],  # terminal state
 }
@@ -529,6 +530,60 @@ def _dispatch_dual_validation_effects(
                 except Exception as e:
                     logger.warning("Jira push failed for test %s: %s", test.id, e, exc_info=True)
 
+        elif event.name == "dual_validation_disputed":
+            # Notify the lead who APPROVED asking them to review the rejection
+            _notify_validation_conflict(db, test, actor)
+
+
+def _notify_validation_conflict(db: Session, test: Test, actor: User | None) -> None:
+    """Notify the lead who APPROVED about the other lead's rejection.
+
+    Tells them: 'The other lead rejected. Review their notes and either
+    change your vote to rejected or discuss with them to resolve.'
+    """
+    from app.models.user import User as UserModel
+
+    red_approved = test.red_validation_status == "approved"
+    blue_approved = test.blue_validation_status == "approved"
+
+    # Identify who approved (they need to be notified)
+    approver_id = None
+    rejector_role = None
+    rejection_notes = None
+
+    if red_approved and test.blue_validation_status == "rejected":
+        approver_id = test.red_validated_by
+        rejector_role = "Blue Lead"
+        rejection_notes = test.blue_validation_notes
+    elif blue_approved and test.red_validation_status == "rejected":
+        approver_id = test.blue_validated_by
+        rejector_role = "Red Lead"
+        rejection_notes = test.red_validation_notes
+
+    if not approver_id:
+        return
+
+    notes_snippet = f': "{rejection_notes[:200]}"' if rejection_notes else ""
+    try:
+        create_notification(
+            db,
+            user_id=approver_id,
+            type="validation_conflict",
+            title="Validation conflict — action required",
+            message=(
+                f"{rejector_role} rejected test '{test.name}' while you approved it{notes_snippet}. "
+                f"Review their reason and either change your decision to 'rejected' "
+                f"or contact {rejector_role} to resolve the disagreement."
+            ),
+            entity_type="test",
+            entity_id=str(test.id),
+        )
+    except Exception as e:
+        logger.warning(
+            "Failed to send conflict notification for test %s: %s",
+            test.id, e, exc_info=True,
+        )
+
 
 def handle_remediation_completed(db: Session, test: Test, user: User) -> Test | None:
     """Create a re-test when remediation is completed.
@@ -681,13 +736,12 @@ def reopen_test(db: Session, test: Test, user: User) -> Test:
     test.blue_validated_at = None
     # test.blue_validation_notes → KEEP (rejection reason / clarification needed)
 
-    # Reset phase timing so the new execution starts fresh
-    test.red_started_at = None
-    test.blue_started_at = None
-    test.blue_work_started_at = None
+    # Phase timing: kept as historical record of the previous attempt.
+    # When the team presses "Start Execution" again, red_started_at will be
+    # overwritten with the new timestamp — no manual reset needed.
+    # Only the active-pause marker is cleared (it should never be set on a
+    # rejected test, but clear it defensively to avoid a stuck timer).
     test.paused_at = None
-    test.red_paused_seconds = 0
-    test.blue_paused_seconds = 0
 
     try:
         from app.services.jira_service import push_test_event