UX polish: toned gold, cleaner labels, dropdown chevrons

- Toned down gold colors for better cross-monitor consistency
  - Header gold: #fee862 → #e5d058
  - Form labels: #ffe699 → #d9c580
- Removed text-shadow/outline from form labels (was smudgy)
- Removed background from nav floating labels
- More subtle nav hover background (halved opacity)
- Gold chevron on all dropdown selects for clarity
- Removed (environment) tag from channel key display
- Simplified channel key config text in about page
- Generate page: icon-only button for channel key

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

frontends/web/templates/index.html

@@ -30,14 +30,14 @@
     transition: all 0.15s ease;
 }
 .home-icon:hover i {
-    color: #fee862;
+    color: #e5d058;
     transform: translateY(-3px);
     filter: drop-shadow(0 5px 4px rgba(0, 0, 0, 0.8));
 }
 .home-icon:hover span {
     opacity: 1;
     transform: translateY(0);
-    color: #fee862;
+    color: #e5d058;
 }
 </style>