Remove everything that can change after first paint

Firefox users saw a flash on the first navigation after an idle spell, and
Chrome occasionally flashed white. Nothing in the network path explained it
(assets are immutable, the stylesheet is render-blocking, a cold Firefox
load paints fully styled), so this removes every remaining way a page could
look different between its first paint and its final state:

- Both Newsreader faces are embedded in the served stylesheet as data: URIs
  (CSP gains `font-src 'self' data:`; the preloads go away). A font fetched
  by URL is applied after first paint whenever the browser has to bring it
  back from disk, which is exactly the "first click after a while" case.
- The cross-document view transition is gone; the operator wants snappy.
- A color-scheme meta, kept in step with the saved theme, so the canvas the
  browser paints before the stylesheet is the right shade.
- The theme toggle's icon and label are chosen by CSS from html[data-theme]
  (set pre-paint by theme.js) instead of being rewritten by app.js.
- Dashboard table filters are rendered by the templates (shown under
  `.has-js`) rather than inserted by app.js, so tables no longer jump.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01MD4VWGq6mGcd8Bg67qyx9k

src/web/tailwind.css

@@ -82,40 +82,6 @@
   @media (prefers-reduced-motion: reduce) { *, *::before, *::after { scroll-behavior:auto !important; transition-duration:0.01ms !important; } }
 }
 
-@view-transition {
-  navigation: auto;
-}
-
-.site-header {
-  view-transition-name: site-header;
-}
-
-::view-transition-old(root),
-::view-transition-new(root) {
-  animation-duration: 140ms;
-  animation-timing-function: ease-out;
-}
-
-::view-transition-group(site-header),
-::view-transition-new(site-header) {
-  animation: none;
-}
-
-::view-transition-old(site-header) {
-  display: none;
-}
-
-@media (prefers-reduced-motion: reduce) {
-  ::view-transition-group(site-header),
-  ::view-transition-old(root),
-  ::view-transition-new(root),
-  ::view-transition-old(site-header),
-  ::view-transition-new(site-header) {
-    animation: none;
-  }
-}
-
-
 @layer components {
   /* ---------- shared controls ---------- */
   .btn, .button { @apply inline-flex min-h-10 items-center justify-center rounded-sm border border-rule-strong bg-transparent px-3 py-1.5 font-sans text-sm font-medium text-ink no-underline duration-150 hover:bg-ink hover:text-paper focus-visible:outline-none focus-visible:ring-2 focus-visible:ring-accent focus-visible:ring-offset-2 focus-visible:ring-offset-paper; transition-property:transform, background-color, color, border-color; }
@@ -231,7 +197,13 @@
   .filters .filter-actions { @apply flex items-center gap-3; }
   .form-inline { @apply flex flex-wrap items-center gap-3 font-sans text-sm; }
   .form-inline label { @apply flex items-center gap-2 text-sm; }
-  .table-filter { @apply my-2 w-80 max-w-full font-sans text-sm; }
+  /* Rendered by the templates but only useful with the script; `has-js` is set pre-paint. */
+  .table-filter { @apply my-2 hidden w-80 max-w-full font-sans text-sm; }
+  .has-js .table-filter { @apply block; }
+  /* Theme toggle: the current theme's icon and label, chosen without script. */
+  [data-theme-icon], [data-theme-label] { display:none; }
+  html:not([data-theme]) [data-theme-icon="system"], html[data-theme="light"] [data-theme-icon="light"], html[data-theme="dark"] [data-theme-icon="dark"] { display:block; }
+  html:not([data-theme]) [data-theme-label="system"], html[data-theme="light"] [data-theme-label="light"], html[data-theme="dark"] [data-theme-label="dark"] { display:inline; }
 
   .pager { @apply flex flex-wrap items-center justify-between gap-x-6 gap-y-2 py-1 font-sans text-sm tabular-nums text-muted; }
   .pager a { @apply text-ink no-underline hover:text-accent; }