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>

internal/web/static/panel.css

@@ -94,8 +94,12 @@ details form { margin-top: 0.6rem; }
    the entries, reading as a third row of navigation. Shortening labels would buy
    the ~200px back but undo the point of naming each entry after its page. Rows
    rather than columns: a two-column grid of entries came out a third taller
-   (107px against 83px) and no easier to read. Entries stay first, in the
-   document order, so tabbing reaches the pages before Sign out. */
+   (107px against 83px) and no easier to read.
+   The session sits on top, at the right edge, and the page entries below — the
+   usual arrangement, and the layout template puts the session first so the
+   reading and tab order follow what the eye sees rather than being flipped by a
+   CSS `order`. The cost is that Sign out is the bar's first tab stop; nothing
+   activates on focus, so that is a reordering, not a hazard. */
 .nav {
   display: flex; flex-direction: column; align-items: stretch;
   gap: 0.5rem; margin-bottom: 1.2rem; padding-bottom: 0.6rem;