Move fastext nav to page top, fix Settings header, add working search

- Fastext colour keys now lead every page but the index, since they're
  the only nav those pages carry; the index keeps them as its closing
  row since its own body is already the full nav.
- Settings page was missing page="settings" in its render_template
  call, so its header silently fell back to "P100 Index".
- Library's search form posted a q param the route never read; it now
  filters the cached Sonarr/Radarr lists and shows matching tiles.
- Discover gained a search bar that queries Ombi (already in front of
  TMDB/TVDB) and lets you add a result straight to Radarr/Sonarr,
  showing "Held" instead of a button for anything already in library.
- Fixed the Add button's success check, which read d.ok against a
  response that actually sets d.success — it reported FAILED even
  when the add worked.

static/js/service.js

@@ -129,7 +129,7 @@
       })
         .then(function (r) { return r.json(); })
         .then(function (d) {
-          if (d && d.ok) {
+          if (d && d.success) {
             btn.classList.add('done');
             btn.textContent = 'ADDED';
           } else {