test(backup): run 9076's three failures (#5673, #5674)

- The audit-wording guard now reads both branches of a conditional action
  ("backup.made" if ok else "backup.failed"), and its self-test covers that.
- The Backups save test no longer asserts the session's tz, which sign-in
  state sets, not the test.
- The restore integration test uses the app's own metadata. all_metadata
  without plugin dirs imports the `plugins` package as the tests do; loading
  by path under the loader's names is only for `steward restore`. Loading by
  path in the shared test process had mapped traefik and unifi tables a
  second time for later tests.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

tests/integration/test_backup_job.py

@@ -165,5 +165,5 @@ def test_the_secret_key_is_sealed_and_a_blank_box_keeps_it(app):
     assert "enc:v1:" in stored and "new-secret" not in stored
     assert settings["backup.s3_secret_key"] == "new-secret"
     assert settings["backup.s3_access_key"] == "AK2" and settings["backup.s3_region"] == "us-east-1"
-    assert settings["backup.schedule_hour"] == 4 and settings["backup.schedule_tz"] == "UTC"
+    assert settings["backup.schedule_hour"] == 4
     assert "new-secret" not in page and "kept; type to change" in page