dev/e2e: wall_clock regression check + deterministic fixture dates

`e2e.sh check` compares every indexed fixture's manifest wall clock with
the `wall_clock` reported by /image/metadata, /memories and
/photos/gps-summary; any disagreement fails.

- Fixture videos are stamped like phone containers: the America/New_York
  wall as a UTC creation_time (the label previously showed the UTC time).
- mtimes are pinned in America/New_York instead of the host's zone.
- The e2e env sets TZ=America/New_York (the #120 preflight): the Windows
  exe has no /etc/timezone, so server_zone() was otherwise None.

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

dev/e2e/e2e.sh

@@ -87,6 +87,10 @@ LOCAL_BIND_URL=
 CORS_ALLOWED_ORIGINS=http://localhost:8081,http://localhost:19006
 SECRET_KEY=e2e-dev-only-secret-not-for-production
 RUST_LOG=info
+# Pin the server zone (ImageApi #120 preflight): the Windows exe has no
+# /etc/timezone, so without this server_zone() is None and assumed_server
+# rows fall back to the process-local offset.
+TZ=America/New_York
 # Fast ingest so a fresh reset is browsable within seconds.
 WATCH_QUICK_INTERVAL_SECONDS=3
 WATCH_FULL_INTERVAL_SECONDS=60
@@ -227,6 +231,8 @@ Usage: dev/e2e/e2e.sh <command>
                      real folder in as media/imported/; the source is read-only)
   reset              stop, wipe db/thumbs/hls, re-copy media, recreate user
   start | stop | restart | status
+  check              verify every fixture's displayed capture time (wall_clock)
+                     on metadata, memories and gps-summary against the manifest
   token              print a fresh JWT for the e2e user
   api METHOD PATH [JSON]
                      authenticated request, e.g. api GET 'photos?path=&recursive=true'
@@ -248,6 +254,7 @@ case "${1:-help}" in
     restart) cmd_stop; cmd_start ;;
     status) cmd_status ;;
     token) login ;;
+    check) E2E_TOKEN="$(login)" python3 "$HERE/check_wall_clock.py" "$STATE/manifest.json" ;;
     api) shift; api "$@" ;;
     logs) tail -f "$LOG" ;;
     info) cmd_info ;;