Modern in the logo's colours, and the logo in the page's mode (#63)

Modern's palette was sampled from the 2004 iPodderX icon: a neutral navy,
its screen blue and amber EQ bars. It now takes the new logo's colours,
the dark half from logo-dark.svg (navy ground, #8fc2ea scale, #ff6a1a
needle) and the light half from logo.svg (sky ground, #2f6aa0 scale, the
needle taken down to #c43e00 so white on it clears AA). The pending amber
and the error red moved apart from the needle's orange, and the sign-in
page's copy of the palette follows.

The pages always showed logo.svg, the light variant, even in a dark
theme; logo-dark.svg was never served. It is now, and the app and admin
pages show whichever matches data-mode, dark until the script says light,
as the palette is. The sign-in page, which has no account's theme, picks
by the system's with <picture>.

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

web/admin.html

@@ -13,7 +13,7 @@
 <!-- The server sends this page, and its script, to admins only. -->
 <header id="topbar">
   <a class="btn ico" href="/" title="Back to iPX" aria-label="Back to iPX" data-icon="left"></a>
-  <img class="logo" src="/logo.svg" alt="" width="26">
+  <img class="logo onlight" src="/logo.svg" alt="" width="26"><img class="logo ondark" src="/logo-dark.svg" alt="" width="26">
   <h1>Admin</h1>
   <span class="grow"></span>
   <nav class="tabs" id="atabs">