fix(settings): close the M3U group editor on any relock

The group management dialog lists every group name, locked ones
included, even when it opened without lock toggles (unreadable lock
store). It now closes on any relock, and the groups view re-checks the
lock state before opening it.

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

docs/architecture/parental-lock.md

@@ -386,7 +386,9 @@ so a cancelled or refused PIN leaves it showing the real state.
   read (`ensureLocksReadable`): a draft taken from the empty fail-closed
   snapshot would erase the real locks on Save if storage recovered in
   between. The M3U and Xtream dialogs then open without lock toggles; the
-  Stalker dialog does not open. Bulk actions stay in the dialog, and while the session is locked
+  Stalker dialog does not open. Every one of them closes on a relock, the
+  M3U one also when it opened without toggles, since it still lists every
+  group name. Bulk actions stay in the dialog, and while the session is locked
   a locked category is not in the rail, so unlocking always goes through
   the "N locked · Enter PIN to show" row or the dialog. The M3U dialog
   hands its lock list back to `ChannelListContainerComponent`, which