feat(design): Warm Cinema redesign + fast-start players

Full visual overhaul from Cyber-Cinematic Glass to "Warm Cinema":
warm charcoal (#0B0908), cream (#F3E9DF), ember (#D9541F).
Fraunces (editorial serif) for display, Karla for body/UI.

Design
- app_colors: new palette, all existing token names preserved,
  plus posterScrim/heroScrim gradients and lift()/emberFocus() shadows
- app_theme: new type scale, tighter radii, 20+ component themes
- mobile_theme aligned on the same tokens
- glass_container: opaque layered surfaces replace glassmorphism;
  adds GlassCard (hover + remote-focus states) and CinemaBackdrop
- players and boot splash restyled (film-leader motif, no web fonts)

Performance
- remove every BackdropFilter (33 call sites): backdrop blur forced a
  full framebuffer read per frame per card, the main scroll jank source
- bundle Fraunces/Karla as assets: google_fonts no longer fetches from
  fonts.gstatic.com at startup
- drop the blocking hls.js CDN script from index.html; no Dart code
  ever used it, only the player iframes need it
- self-host hls.js/mpegts.js and load them on demand, so ~213 KB of
  mpegts is never downloaded for HLS streams
- bound image decode size on 10 sites: a 40-poster grid drops from
  ~240 MB to a few tens of MB of GPU memory

Players (new shared engine: web/xf-player-core.js)
- event-driven start instead of a 200 ms buffer poll plus a 1.5 s wait
- initialLiveManifestSize 3 -> 1, liveSyncDurationCount 10 -> 2,
  startFragPrefetch on, testBandwidth off
- MPEG-TS initial stash 512 KB -> 64 KB
- adaptive escalation fast -> balanced -> safe on repeated stalls
  (60 s rolling window), applied live for HLS so there is no visible cut

Pre-existing build breakage fixed along the way
- undefined AppColors.shimmer, AppTheme.durationXs and spacing8/12/16/32
- broken relative imports in channel_card and quality_selector_widget
- missing GlassCard widget and hasBorder/showShadow parameters

Also resolves a leftover unmerged .claude/settings.local.json by
keeping the remote version.

Still broken (pre-existing, dead code, not reachable from main.dart):
recommendations_provider.dart and continue_watching_widget.dart import
a models/playlist.dart that no longer exists.

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

lib/core/widgets/hero_carousel.dart

@@ -179,6 +179,9 @@ class _HeroCarouselState extends State<HeroCarousel>
           Image.network(
             item.imageUrl!,
             fit: BoxFit.cover,
+            // Le heros est plein ecran : plafond a 1280 px, au-dela le gain
+            // visuel est nul et le cout de decodage explose.
+            cacheWidth: 1280,
             errorBuilder: (context, error, stackTrace) {
               return Container(
                 color: AppColors.surface,
@@ -220,7 +223,7 @@ class _HeroCarouselState extends State<HeroCarousel>
             ),
             child: Text(
               item.badge!,
-              style: GoogleFonts.inter(
+              style: GoogleFonts.karla(
                 fontSize: 12,
                 fontWeight: FontWeight.w700,
                 color: AppColors.primary,
@@ -233,7 +236,7 @@ class _HeroCarouselState extends State<HeroCarousel>
           item.title,
           maxLines: 2,
           overflow: TextOverflow.ellipsis,
-          style: GoogleFonts.outfit(
+          style: GoogleFonts.karla(
             fontSize: 48,
             fontWeight: FontWeight.w800,
             color: AppColors.textPrimary,
@@ -247,7 +250,7 @@ class _HeroCarouselState extends State<HeroCarousel>
             item.subtitle!,
             maxLines: 2,
             overflow: TextOverflow.ellipsis,
-            style: GoogleFonts.inter(
+            style: GoogleFonts.karla(
               fontSize: 16,
               fontWeight: FontWeight.w400,
               color: AppColors.textSecondary,
@@ -292,7 +295,7 @@ class _HeroCarouselState extends State<HeroCarousel>
                           const SizedBox(width: 8),
                           Text(
                             'Play',
-                            style: GoogleFonts.inter(
+                            style: GoogleFonts.karla(
                               fontSize: 16,
                               fontWeight: FontWeight.w700,
                               color: AppColors.primary,
@@ -330,7 +333,7 @@ class _HeroCarouselState extends State<HeroCarousel>
                         const SizedBox(width: 8),
                         Text(
                           'More Info',
-                          style: GoogleFonts.inter(
+                          style: GoogleFonts.karla(
                             fontSize: 16,
                             fontWeight: FontWeight.w700,
                             color: AppColors.textPrimary,