New markup over an old stylesheet

Reported from a desktop browser: a stray close button beside the logo, badly
drawn, and a page that would not scroll. None of it was in the code that was
running -- it was the code the browser had not fetched.

The worker caches /static/ under a cache named for the release while the files
in it carried no version, and a page is fetched network-first. That only ever
worked because the worker used to seize every open tab the instant it installed
and wipe the old cache. 1.1.0 stopped it doing that, rightly -- it was swapping
stylesheets out from under a streaming reply -- and a momentary mismatch became
a permanent one: new markup over the previous release's CSS for as long as the
old worker lived. `.sidebar__close` had no rule there, so `.btn--icon` made it
inline-flex: visible everywhere, placed by nothing.

Every /static/ URL carries the release now, written by `templating.asset` and
precached by `sw.js:versioned` -- both halves, because caches.match compares the
query too and precaching the bare path would cache entries nothing requests.
Self-correcting: updating is enough.

The header was also a brand with a button appended and margin-left:auto doing
the placing, which holds exactly while that button is last. Two slots now: a
brand that shrinks and truncates, and a rail on the trailing edge.

Verified before changing anything: with the current stylesheet the button is
display:none at 1280 and, with thirty chats and forty messages, both scrollers
scroll. The first measurement said the thread did not -- that was
scroll-behavior: smooth reporting where it started.

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

src/lembas/web/static/js/sw.js

@@ -50,6 +50,18 @@ var SHELL = [
   "/static/img/apple-touch-icon-180.png",
 ];
 
+/* The URL a page will actually ask for.
+
+   Every `/static/` link carries `?v=<release>` -- see `templating.asset` -- and
+   `caches.match` compares the whole URL, query included. So precaching the bare
+   path would fill the cache with entries no page ever requests, and every asset
+   would go to the network on every load while looking perfectly cached.
+
+   `/offline` is a route rather than an asset and is left alone. */
+function versioned(path) {
+  return path.indexOf("/static/") === 0 ? path + "?v=" + VERSION : path;
+}
+
 self.addEventListener("install", function (event) {
   event.waitUntil(
     caches.open(CACHE).then(function (cache) {
@@ -57,7 +69,8 @@ self.addEventListener("install", function (event) {
       // and the whole feature silently off, so each entry is added on its own.
       return Promise.all(
         SHELL.map(function (path) {
-          return cache.add(new Request(path, { cache: "reload" })).catch(function () {});
+          return cache.add(new Request(versioned(path), { cache: "reload" }))
+            .catch(function () {});
         })
       );
     })