design: the preflight mockup goes - the page was dropped on 2026-10-13

Owner, 2026-10-18: "Чисти этот хвост." Preflight as a page of its own was
dropped on 2026-10-13 (roadmap.md § Dropped): its installation checks went
to Server › Health (health-setup-checks, 2.11.0) and its test e-mail to a
form of its own (test-email, 2.12.0). The mockup still drew it and every
mockup's navigation still linked it.

- panel/src/preflight.html and its built page deleted; build.py's Server
  group loses the entry, and the 39 pages are rebuilt (each one only loses
  that link, in the navbar and the touch menu).
- check.py --write: outlines.json loses the "preflight" key; 31 screens,
  0 violations.
- index.html and panel-redesign.md § Room for roadmap items no longer list it.

The guard's deferredScreens entry goes in the next commit, on its own.

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

docs/assets/panel-redesign/index.html

@@ -36,7 +36,7 @@
         <a href="panel/in-queue.html">Queue</a> (empty state)<br>
         <a href="panel/in-quarantine.html">Quarantine</a> · <a href="panel/in-quarantine-message.html">held message</a> ·
         <a href="panel/in-filter-lists.html">Filter lists</a> — roadmap items, drawn as their target look</td></tr>
-      <tr><th>Server</th><td><a href="panel/health.html">Health</a> · <a href="panel/preflight.html">Preflight</a> (roadmap) · <a href="panel/system-log.html">System log</a> ·
+      <tr><th>Server</th><td><a href="panel/health.html">Health</a> · <a href="panel/system-log.html">System log</a> ·
         <a href="panel/backup.html">Backup</a> · <a href="panel/users.html">Users</a> · <a href="panel/user.html">user form</a> ·
         <a href="panel/user-delete.html">delete user</a> · <a href="panel/settings.html">Settings</a></td></tr>
       <tr><th>User menu</th><td><a href="panel/account.html">Account</a> · <a href="panel/help.html">Help</a></td></tr>