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/theme.js

@@ -5,7 +5,9 @@
   var el = document.documentElement;
   var saved = null;
   try { saved = localStorage.getItem('theme'); } catch (e) { /* private mode */ }
+  var THEMES = ['light', 'dark', 'neon', 'terminal', 'blueprint', 'sunset'];
   var theme = saved || el.dataset.defaultTheme || 'light';
-  if (theme !== 'light' && theme !== 'dark') theme = 'light';
+  if (THEMES.indexOf(theme) === -1) theme = 'light';
   el.dataset.theme = theme;
+  el.dataset.themes = THEMES.join(',');
 })();