fix(m7): stamping executed_at no longer requires a prior state transition

User reported `HTTP 400 — executed_at can only be set when state is
executed/reviewed_by_blue` when typing the timestamp inline in the new
scenario table. The state-gate predates the simplified UX — it made
sense back when the workflow was "Mark executed button + override
toggle", but the user has since asked for a single freely-typeable
datetime input.

- update_mission_test_fields drops the state check. Stamping a non-null
  executed_at while state ∈ {pending, skipped, blocked} now auto-promotes
  the state to `executed` in the same write. The promotion is gated by
  the same mission.write_red_fields perm that executed_at already
  required — no privilege escalation.
- MissionTestPage.tsx drops the state-based UI gate on canEditExecutedAt;
  red perm alone now unlocks the input regardless of state.
- Replaced the old "rejection while pending" test with two new tests:
  pending→executed via inline stamp + blue 403, and skipped→executed via
  inline stamp.
- 139 pytest green.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

backend/tests/test_mission_tests.py

@@ -569,18 +569,33 @@ def test_mark_executed_stamps_executed_at(
     assert body["executed_at_overridden"] is False
 
 
-def test_executed_at_override_requires_red_perm_and_state(
+def test_red_setting_executed_at_on_pending_auto_transitions_to_executed(
     client, admin_token, catalogue, red_user, blue_user
 ):
+    """Post-amendement (2026-05-15): the red team should be able to stamp
+    executed_at inline without first POST-ing /transition. The service
+    auto-flips state pending→executed in the same write so the persisted
+    row stays internally consistent.
+
+    Blue still cannot touch executed_at (red-side field) — perm gating is
+    unchanged.
+    """
     mission = _make_mission(
-        client, admin_token, name="m7-override",
+        client, admin_token, name="m7-exec-at-pending",
         scenario_id=catalogue["scenario"]["id"],
         red_id=red_user["id"], blue_id=blue_user["id"],
     )
     tid = _first_test_id(mission)
 
-    # Override while still pending → invalid_request (no executed milestone yet).
-    bad = client.put(
+    # Sanity: starts as pending.
+    detail = client.get(
+        f"/api/v1/missions/{mission['id']}/tests/{tid}",
+        headers=_bearer(red_user["token"]),
+    )
+    assert detail.get_json()["state"] == "pending"
+
+    # Red stamps executed_at directly — must succeed and bump the state.
+    stamped = client.put(
         f"/api/v1/missions/{mission['id']}/tests/{tid}",
         headers=_bearer(red_user["token"]),
         json={
@@ -588,39 +603,49 @@ def test_executed_at_override_requires_red_perm_and_state(
             "executed_at_overridden": True,
         },
     )
-    assert bad.status_code == 400, bad.get_data(as_text=True)
+    assert stamped.status_code == 200, stamped.get_data(as_text=True)
+    body = stamped.get_json()
+    assert body["state"] == "executed"
+    assert body["executed_at"].startswith("2026-05-14T10:00:00")
+    assert body["executed_at_overridden"] is True
 
-    # Mark executed first so we're allowed to override.
-    client.post(
-        f"/api/v1/missions/{mission['id']}/tests/{tid}/transition",
-        headers=_bearer(red_user["token"]),
-        json={"target_state": "executed"},
-    )
-
-    # Blue cannot override (executed_at is a red field).
+    # Blue cannot touch executed_at — red-side field.
     forbidden = client.put(
         f"/api/v1/missions/{mission['id']}/tests/{tid}",
         headers=_bearer(blue_user["token"]),
-        json={
-            "executed_at": "2026-05-14T10:00:00+00:00",
-            "executed_at_overridden": True,
-        },
+        json={"executed_at": "2026-05-14T11:00:00+00:00"},
     )
     assert forbidden.status_code == 403
 
-    # Red successfully overrides.
-    ok = client.put(
+
+def test_red_setting_executed_at_from_skipped_state_auto_transitions(
+    client, admin_token, catalogue, red_user
+):
+    """Skipped → executed by stamping a timestamp: same implicit transition
+    so the operator who marked the test skipped by mistake can simply type
+    the actual execution time."""
+    mission = _make_mission(
+        client, admin_token, name="m7-exec-at-skipped",
+        scenario_id=catalogue["scenario"]["id"], red_id=red_user["id"],
+    )
+    tid = _first_test_id(mission)
+    # Move to skipped first.
+    skip = client.post(
+        f"/api/v1/missions/{mission['id']}/tests/{tid}/transition",
+        headers=_bearer(red_user["token"]),
+        json={"target_state": "skipped"},
+    )
+    assert skip.status_code == 200
+    assert skip.get_json()["state"] == "skipped"
+
+    # Stamp executed_at inline → should land in executed.
+    stamped = client.put(
         f"/api/v1/missions/{mission['id']}/tests/{tid}",
         headers=_bearer(red_user["token"]),
-        json={
-            "executed_at": "2026-05-14T10:00:00+00:00",
-            "executed_at_overridden": True,
-        },
+        json={"executed_at": "2026-05-14T12:00:00+00:00"},
     )
-    assert ok.status_code == 200, ok.get_data(as_text=True)
-    body = ok.get_json()
-    assert body["executed_at_overridden"] is True
-    assert body["executed_at"].startswith("2026-05-14T10:00:00")
+    assert stamped.status_code == 200, stamped.get_data(as_text=True)
+    assert stamped.get_json()["state"] == "executed"
 
 
 def test_state_machine_rejects_invalid_transitions(