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/mobile/features/iptv/widgets/mobile_settings_tab.dart

@@ -1,4 +1,4 @@
-import 'package:flutter/material.dart';
+import 'package:flutter/material.dart';
 import 'package:flutter_riverpod/flutter_riverpod.dart';
 import 'package:go_router/go_router.dart';
 import 'package:google_fonts/google_fonts.dart';
@@ -398,7 +398,7 @@ class _SectionHeader extends StatelessWidget {
       padding: const EdgeInsets.only(left: 8, bottom: 8),
       child: Text(
         title,
-        style: GoogleFonts.inter(
+        style: GoogleFonts.instrumentSans(
           fontSize: 14,
           fontWeight: FontWeight.w600,
           color: AppColors.onSurfaceVariant,