feat(m7-amend2): implicit lifecycle — writes drive state, no workflow UI

User: «Enlève également le workflow d'un test, quand on saisit des
informations côtés redteam cela signifie qu'il a été exécuté et donc
en attente d'une review blueteam.»

Backend (update_mission_test_fields)
- At the end of every PUT, inspect the touched-field set:
  - any red write on state in {pending, skipped, blocked} → state=executed
    + auto-stamp executed_at=now() if absent
  - any blue write on state=executed → state=reviewed_by_blue
- /transition endpoint kept for back-fill/admin use, not called from UI.

Frontend MissionTestPage
- Removed the transition-buttons header block and the `transition`
  mutation. State pill stays as a passive indicator.
- New labels: "Not started" / "Awaiting review" / "Reviewed" describe
  the implicit lifecycle, no longer exposing the state-machine concept.

E2E
- The SPA test that clicked `transition-executed` now verifies the
  implicit promotion: typing red fields and saving flips the pill from
  "Not started" → "Awaiting review", no button click required.

Spec
- §4 reword: "Cycle de vie implicite, piloté par les écritures" replaces
  the old "Workflow par test instance" bullet.

Tests
- 3 new pytest: red_command-alone implicit execute + auto-stamp,
  blue write promotes executed→reviewed, blue write on pending no-op.
- 142 pytest + 49 Playwright green.

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

backend/tests/test_mission_tests.py

@@ -618,6 +618,82 @@ def test_red_setting_executed_at_on_pending_auto_transitions_to_executed(
     assert forbidden.status_code == 403
 
 
+def test_red_writing_any_red_field_implicitly_executes_and_stamps(
+    client, admin_token, catalogue, red_user
+):
+    """Post-amendement 2026-05-15 bis: the explicit state-machine workflow
+    is gone. Writing ANY red field on a non-executed test promotes the
+    state to `executed`; if the operator didn't supply an `executed_at`,
+    the service auto-stamps `now()` so the persisted row is internally
+    consistent."""
+    mission = _make_mission(
+        client, admin_token, name="m7-implicit-execute",
+        scenario_id=catalogue["scenario"]["id"], red_id=red_user["id"],
+    )
+    tid = _first_test_id(mission)
+    r = client.put(
+        f"/api/v1/missions/{mission['id']}/tests/{tid}",
+        headers=_bearer(red_user["token"]),
+        json={"red_command": "whoami /priv"},  # no executed_at!
+    )
+    assert r.status_code == 200, r.get_data(as_text=True)
+    body = r.get_json()
+    assert body["state"] == "executed"
+    assert body["red_command"] == "whoami /priv"
+    assert body["executed_at"] is not None  # auto-stamped
+    assert body["executed_at_overridden"] is False
+
+
+def test_blue_writing_any_blue_field_promotes_executed_to_reviewed(
+    client, admin_token, catalogue, red_user, blue_user
+):
+    """A blue write on an executed test implicitly promotes the state to
+    `reviewed_by_blue` — no explicit transition required from the UI."""
+    mission = _make_mission(
+        client, admin_token, name="m7-implicit-review",
+        scenario_id=catalogue["scenario"]["id"],
+        red_id=red_user["id"], blue_id=blue_user["id"],
+    )
+    tid = _first_test_id(mission)
+    # Red executes (also implicit).
+    client.put(
+        f"/api/v1/missions/{mission['id']}/tests/{tid}",
+        headers=_bearer(red_user["token"]),
+        json={"red_command": "powershell -enc Y2FsYw=="},
+    )
+    # Blue reviews by writing a comment — state should auto-promote.
+    r = client.put(
+        f"/api/v1/missions/{mission['id']}/tests/{tid}",
+        headers=_bearer(blue_user["token"]),
+        json={"blue_comment_md": "alert raised on EDR"},
+    )
+    assert r.status_code == 200, r.get_data(as_text=True)
+    body = r.get_json()
+    assert body["state"] == "reviewed_by_blue"
+
+
+def test_blue_write_on_pending_does_not_auto_execute(
+    client, admin_token, catalogue, blue_user
+):
+    """A blue write on a still-pending test does NOT auto-execute — only
+    red's writes imply execution (per user feedback: 'quand on saisit des
+    informations côtés redteam cela signifie qu'il a été exécuté')."""
+    mission = _make_mission(
+        client, admin_token, name="m7-blue-on-pending",
+        scenario_id=catalogue["scenario"]["id"], blue_id=blue_user["id"],
+    )
+    tid = _first_test_id(mission)
+    r = client.put(
+        f"/api/v1/missions/{mission['id']}/tests/{tid}",
+        headers=_bearer(blue_user["token"]),
+        json={"blue_comment_md": "pre-emptive note"},
+    )
+    assert r.status_code == 200
+    body = r.get_json()
+    assert body["state"] == "pending"  # unchanged
+    assert body["executed_at"] is None  # not stamped
+
+
 def test_red_setting_executed_at_from_skipped_state_auto_transitions(
     client, admin_token, catalogue, red_user
 ):