panel: put the session row on top of the nav bar

The two rows were the right call; the order was not. The session block
belongs at the top right, where a signed-in user expects it, with the
page entries under it and the active one sitting against the bar's
bottom border.

Done by moving the session div ahead of the links div in the layout
rather than with a CSS `order`, so the reading and tab order still follow
what the eye sees. That does make Sign out the bar's first tab stop --
the same as on any site with a user menu up there, and nothing activates
on focus, so it is a reordering rather than a hazard.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

CHANGELOG.md

@@ -31,11 +31,10 @@ Format follows [Keep a Changelog](https://keepachangelog.com/en/1.1.0/); version
   no exemption from the panel's Content-Security-Policy — and are hidden from
   screen readers, which still announce the label alone.
 
-- panel: the navigation bar is laid out as two rows on purpose — the page
-  entries, then the signed-in user, Account and Sign out along the right edge.
-  It no longer fits on one line and used to wrap on its own, which left the
-  session block sitting left-aligned under the entries as if it were more
-  navigation.
+- panel: the navigation bar is laid out as two rows on purpose — the signed-in
+  user, Account and Sign out along the top right, the page entries below. It no
+  longer fits on one line and used to wrap on its own, which left the session
+  block sitting left-aligned under the entries as if it were more navigation.
 
 ## [0.2.0] - 2026-08-03