feat(design): Projector Noir theme - tungsten amber on film-black

Full visual refonte replacing the generic neon-blue glass look:

- palette: warm film-black surface ladder, tungsten amber primary,
  warm taupe secondary, verdigris teal tertiary; semantic and
  category colors retuned to match (coral live, gold movies)
- typography: Syne (display/headlines) + Instrument Sans (body/UI)
  replace Space Grotesk/Inter/Outfit across all screens
- glassmorphism tokens warmed (amber inner glow, warm-white borders)
- web player theme.css + index.html loader mirror the new tokens
- hardcoded Colors.blue* in streaming settings and recordings tabs
  now use AppColors tokens
- DESIGN_SYSTEM.md updated to v3.0 Projector Noir

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

lib/features/admin/screens/admin_panel.dart

@@ -152,7 +152,7 @@ class _AdminContentState extends ConsumerState<AdminContent>
                 const SizedBox(width: 8),
                 Text(
                   label,
-                  style: GoogleFonts.inter(
+                  style: GoogleFonts.instrumentSans(
                     fontWeight: FontWeight.w600,
                     fontSize: 14,
                     color: isSelected ? AppColors.textPrimary : AppColors.textSecondary,