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/speculation.json

@@ -0,0 +1,26 @@
+{
+  "prerender": [
+    {
+      "source": "document",
+      "where": {
+        "and": [
+          { "href_matches": ["/", "/issues/*"] },
+          { "not": { "href_matches": ["/logout", "/rate", "/static/*", "/*\\?*"] } }
+        ]
+      },
+      "eagerness": "moderate"
+    }
+  ],
+  "prefetch": [
+    {
+      "source": "document",
+      "where": {
+        "and": [
+          { "href_matches": ["/dashboard", "/dashboard/*"] },
+          { "not": { "href_matches": ["/logout", "/rate", "/static/*", "/*\\?*"] } }
+        ]
+      },
+      "eagerness": "moderate"
+    }
+  ]
+}