Fix design-review findings: self-linking nav, colour reuse, badge clash

From a frontend-design skill review of all pages, after last session's
chrome changes (top nav, all-tabs nav, header download row):

- The top/closing fastext nav now mutes the entry matching the current
  page (.fastext-here) instead of rendering a link to the page you're
  already on.
- Colour in fastext is reserved for the four entries that still carry
  a real keyboard shortcut (r/g/y/c); the other four render in plain
  ink instead of reusing k-red/k-green/k-yellow/k-cyan for a
  destination they don't semantically mean (e.g. Requests no longer
  shows in the app's own off-air red).
- Discover's badge slot meant "critic score" on its RT tiles and
  "release year" on its new search tiles at the same time. Search
  results (Library and Discover) now fold year/held-state into the
  sub-line instead, leaving the badge exclusively for critic score.
- System's Transmission rows now carry a small ↗ glyph, since they
  silently changed from in-app navigation to opening each service's
  own UI in a new tab with no visual cue.
- SABnzbd polling drops from 5s to 20s on pages that only show the
  header's download figure (everywhere but System/Activity, which
  keep 5s for their own live figures) — a number idle 95% of the time
  doesn't need second-level freshness sitewide.
- DESIGN.md's fastext description, now-current per this session's nav
  changes.

CLAUDE.md

@@ -107,7 +107,12 @@ the user's Unraid home server. Server-side project directory is still named
     with `HOME_FASTEXT`, the original four-entry row, as its own closing
     line, since its body already lists every destination once. Only
     those original four (Index/Library/Discover/System) carry an `r`/
-    `g`/`y`/`c` keyboard shortcut; the rest are click-only.
+    `g`/`y`/`c` keyboard shortcut and a colour swatch — colour is
+    semantic everywhere else in this app, so the other four entries
+    render in plain ink rather than reusing one of the four colours for
+    a destination it doesn't mean. Whichever entry matches the current
+    page renders as a `.fastext-here` span instead of a link — a page
+    linking to itself did nothing, so it isn't offered as a click.
   - **Nothing is clipped, hidden, or sticky.** All seven page numbers and
     every fastext entry stay visible at every width, reflowing to another
     row rather than scrolling, truncating, or folding into a menu. No