feat: 5 dramatic extra themes (neon/terminal/blueprint/sunset) + board/review/layout polish

- Themes: add neon (cyber gradient), terminal (green CRT), blueprint (graph
  paper) and sunset (vaporwave) alongside the default Light (Y2K paper) and
  Dark. Theme toggle now cycles all; profile selector lists them; server
  validates against a shared whitelist.
- Bounty cards now show the project (customer) name.
- Remove the celebratory emoji from the empty Review Queue.
- Full-width h1 underline rule; My Tasks columns stack vertically for more
  room per task; card action buttons wrap/right-align so they never overflow.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

web/static/js/reviews.js

@@ -26,7 +26,7 @@ async function load() {
       return card;
     }));
     if (!res.tasks.length) {
-      host.innerHTML = '<p class="muted">Nothing waiting for review. 🎉</p>';
+      host.innerHTML = '<p class="muted">Nothing waiting for review.</p>';
     }
   } catch (e) { errorBox.textContent = e.message; }
 }