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.

templates/discover.html

@@ -27,8 +27,12 @@
       {{ service_error('Sonarr/Radarr', search.error) }}
     {% elif search.results %}
       <div class="tt-tiles">
+        {#- No badge here: the badge slot means "critic score" below,
+            from the RT feed. A search result has no score, so its
+            year and held-state live in the sub-line instead of
+            overloading that slot with a second meaning. -#}
         {% for it in search.results %}
-          {{ tile(it.title, it.kind ~ (' · Held' if it.held else ''), it.poster, it.year, ('' if it.held else '+ Add'), it.target) }}
+          {{ tile(it.title, it.kind ~ (' · ' ~ it.year if it.year else '') ~ (' · Held' if it.held else ''), it.poster, '', ('' if it.held else '+ Add'), it.target) }}
         {% endfor %}
       </div>
     {% else %}