fix(m7): red write always lands on executed + state pill out of Commentaires

User reported two issues on the scenario table:

1. After filling only red_command + executed_at, the pill read
   "Reviewed" instead of "Awaiting review". Cause: the auto-promotion
   was gated on `state in {pending, skipped, blocked}`, so a test that
   blue had already reviewed stayed in `reviewed_by_blue` after a red
   edit. That contradicts the implicit lifecycle (red modifying a
   reviewed test invalidates the review).
2. The state pill lived inside the Commentaires column, polluting a
   cell meant for blue-team comments.

Fixes
- backend/app/services/mission_tests.py: any red-side write now lands
  the state on `executed` unconditionally (including from
  `reviewed_by_blue`). Same-PUT red+blue still flows
  executed → reviewed_by_blue.
- frontend/src/pages/MissionScenarioTable.tsx: state pill moves from
  CommentairesCell to the Test column (top of the row, above the
  snapshot name + MITRE chips). Commentaires now holds only the
  detection_level pill + blue_comment_md.

Tests
- New pytest: `test_red_write_on_reviewed_reverts_to_executed` —
  reviewed_by_blue + red edit ⇒ executed. 143 pytest green.

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

backend/tests/test_mission_tests.py

@@ -644,6 +644,41 @@ def test_red_writing_any_red_field_implicitly_executes_and_stamps(
     assert body["executed_at_overridden"] is False
 
 
+def test_red_write_on_reviewed_reverts_to_executed(
+    client, admin_token, catalogue, red_user, blue_user
+):
+    """When red modifies a test that blue had already reviewed, the state
+    reverts to `executed` (awaiting re-review). The red edits invalidate
+    the previous review — user feedback 2026-05-15 ter."""
+    mission = _make_mission(
+        client, admin_token, name="m7-red-after-review",
+        scenario_id=catalogue["scenario"]["id"],
+        red_id=red_user["id"], blue_id=blue_user["id"],
+    )
+    tid = _first_test_id(mission)
+    # Red executes.
+    client.put(
+        f"/api/v1/missions/{mission['id']}/tests/{tid}",
+        headers=_bearer(red_user["token"]),
+        json={"red_command": "first attempt"},
+    )
+    # Blue reviews — state becomes reviewed_by_blue.
+    blue_done = client.put(
+        f"/api/v1/missions/{mission['id']}/tests/{tid}",
+        headers=_bearer(blue_user["token"]),
+        json={"blue_comment_md": "alert raised"},
+    )
+    assert blue_done.get_json()["state"] == "reviewed_by_blue"
+    # Red modifies their command — state should drop back to executed.
+    re_red = client.put(
+        f"/api/v1/missions/{mission['id']}/tests/{tid}",
+        headers=_bearer(red_user["token"]),
+        json={"red_command": "second attempt"},
+    )
+    assert re_red.status_code == 200
+    assert re_red.get_json()["state"] == "executed"
+
+
 def test_blue_writing_any_blue_field_promotes_executed_to_reviewed(
     client, admin_token, catalogue, red_user, blue_user
 ):