design: local-time - times without UTC, the zone on Settings

Agreed with the owner on 2026-10-13 (the panel in a chosen zone, "today"
that zone's day, the UTC labels gone) and settled on 2026-10-16/17: the
container runs in his zone ("Контейнер в моем поясе") - TZ in .env, read
by every program at its start - so the zone is shown on Settings, not
chosen there ("Да"), as the level-1 limit is.

Every mockup loses "UTC": the column heads are Time, Received, Held,
Arrived; a stamp is a date and a time. Settings gets box 05, Time zone,
read-only: the zone, its offset, where it is set, and that every time and
day of the panel is that zone's, as are mail.log's stamps. The help's
Settings topic says so. outlines.json: settings gains the box. check.py: 0
violations.

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

docs/assets/panel-redesign/panel/outlines.json

@@ -403,7 +403,8 @@
     {
      "is-6": [
       "box[Notification mail]:record×2",
-      "box[Sending rate limits]:body"
+      "box[Sending rate limits]:body",
+      "box[Time zone]:body"
      ]
     }
    ]