UI pass: nav state, ears, feeds table, font flash, faster navigation

- Issue pages highlight Archive instead of Latest unless the issue is the
  newest one (IssueView::is_latest), with a router test.
- The ears row is empty by default and says "Dashboard" on dashboard pages;
  "Morning edition" only survives on the empty-state hero.
- Run page: the Feeds card table is fixed-layout and truncates long feed
  names with the full title on hover instead of pushing the entries column
  out of the card.
- Static assets are content-hashed, so serve them immutable for a year;
  preload both Newsreader faces and use font-display: block so a cache
  revalidation never paints the fallback serif first. Persisted details
  state is restored pre-paint from theme.js.
- Cross-document view transitions (140 ms fade, masthead held still) and
  Speculation Rules (prerender reader pages, prefetch dashboard pages on
  hover) served from /static/speculation.json via the Speculation-Rules
  header, which the CSP would otherwise block inline. No client router.
- Dashboard nav gets the same accent underline as the site nav; 40 px
  targets for the theme toggle, account link and dashboard nav.

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

src/web/static/theme.js

@@ -9,4 +9,23 @@
   } catch (_) {
     document.documentElement.removeAttribute("data-theme");
   }
+
+  // Restore persisted disclosures as the parser creates them. This head script
+  // runs before paint, so a cold app.js request cannot expose the server-default
+  // open state and then shift the dashboard when the script finally arrives.
+  const restoreDetails = (root) => {
+    const details = [];
+    if (root.nodeType === Node.ELEMENT_NODE && root.matches("details[id]")) details.push(root);
+    root.querySelectorAll?.("details[id]").forEach((element) => details.push(element));
+    details.forEach((element) => {
+      try {
+        element.open = localStorage.getItem("details:" + element.id) === "open";
+      } catch (_) {}
+    });
+  };
+  const detailsObserver = new MutationObserver((records) => {
+    records.forEach((record) => record.addedNodes.forEach(restoreDetails));
+  });
+  detailsObserver.observe(document.documentElement, { childList: true, subtree: true });
+  document.addEventListener("DOMContentLoaded", () => detailsObserver.disconnect(), { once: true });
 })();