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>

CHANGELOG.md

@@ -4,6 +4,30 @@ All notable changes to this project will be documented here. Format: [Keep a Cha
 
 ## [Unreleased]
 
+### Fixed (post-amendement 2026-05-15) — stamping executed_at no longer needs a prior state transition
+
+User feedback: when a red user typed `executed_at` inline on a pending test
+in the new scenario table, the backend rejected with `HTTP 400 — executed_at
+can only be set when state is executed/reviewed_by_blue`. The state-gate
+was a holdover from the original "Mark executed button + override toggle"
+workflow; it made no sense once the UX let the operator type the time
+directly.
+
+- `update_mission_test_fields` (`backend/app/services/mission_tests.py`) no
+  longer rejects writes based on the source state. Stamping a non-null
+  `executed_at` while state ∈ {`pending`, `skipped`, `blocked`} now
+  auto-promotes the state to `executed` in the same write. The promotion
+  rides on the same `mission.write_red_fields` perm that the executed_at
+  field already required — no privilege escalation.
+- `MissionTestPage.tsx` drops the state-based gate on `canEditExecutedAt`:
+  the field is editable any time the viewer holds `mission.write_red_fields`.
+- Tests: `test_executed_at_override_requires_red_perm_and_state` was the
+  old guard; it's split into two new cases — `test_red_setting_executed_at_on_pending_auto_transitions_to_executed`
+  (pending → executed via inline stamp, blue still 403'd) and
+  `test_red_setting_executed_at_from_skipped_state_auto_transitions`
+  (skipped → executed via the same path).
+- Total: **139 pytest** green.
+
 ### Added — M7 amendment (2026-05-15) — blue review fields + full-width scenario table
 
 User feedback after the M7 ship: the blue team used to maintain 5 extra