feat: security hardening, streaming overhaul, design polish, tests

Security:
- Replace unsalted SHA-256 password hashing with bcrypt (lazy rehash on login)
- Add authenticated /api/xtream-api gateway: Xtream credentials are injected
  server-side and never sent to the frontend; /api/playlists no longer
  returns passwords
- Redact credentials from all logs (login body, proxy/FFmpeg/scheduler URLs)
- Add auth to recordings, EPG, season-passes and streaming routes
  (HttpOnly session cookie for hls.js; loopback bypass for local FFmpeg)
- Lock player postMessage to same-origin in both directions
- Vendor and pin hls.js 1.6.7 / mpegts.js 1.7.3 (drop CDN @latest)
- Fix rate limiter (client IP was never resolved), add login rate limit,
  restrict CORS, add CSP Report-Only, block private-IP SSRF targets,
  fix path traversal in recording log retrieval, chmod 777 -> 770
- Remove dead HiveService (seeded admin/admin into IndexedDB with SHA-256)
- Fix authMiddleware not populating 'user' context (getPlaylist ignored the
  logged-in user; admin purge always returned 403)

Streaming:
- New FfmpegSessionManager: process registry, idle reaper (4 min live /
  15 min VOD), orphan cleanup at startup, clean SIGTERM shutdown,
  fast-fail with stderr instead of 30 s timeout
- Quality selection (source/high/medium/low) for live and VOD; source mode
  streams with -c:v copy (zero transcoding); selector wired into the player
- Concurrent recordings (MAX_CONCURRENT_RECORDINGS, default 2); conflicts
  retry on the next tick instead of silently failing
- Lower live latency (HLS window 20 -> 10 segments, liveSync 10 -> 3)
- Fix recording log lookup (.mp4 vs .mkv mismatch)

Design:
- Replace hardcoded colors with AppColors tokens (12 files)
- web/theme.css syncs HTML players with the Flutter palette
- DPAD/keyboard navigation (arrow-key focus, player shortcuts)
- Tooltips on player icon buttons, Semantics on content cards
- Remove 7 dead widgets broken since the Stitch merge

Quality:
- bin/test/: 21 unit tests (bcrypt, redaction, traversal, SSRF, recording
  conflicts) plus a quality-selector widget test
- GitHub Actions CI (analyze + test + build web)
- Archive stale status docs into docs/archive/

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

lib/core/widgets/tv_focusable_card.dart

@@ -14,6 +14,9 @@ class TvFocusableCard extends StatefulWidget {
   final bool autofocus;
   final double borderRadius;
 
+  /// Accessibility label announced by screen readers (e.g. channel title).
+  final String? semanticLabel;
+
   const TvFocusableCard({
     super.key,
     required this.child,
@@ -24,6 +27,7 @@ class TvFocusableCard extends StatefulWidget {
     this.focusColor,
     this.autofocus = false,
     this.borderRadius = 12.0,
+    this.semanticLabel,
   });
 
   @override
@@ -84,7 +88,10 @@ class _TvFocusableCardState extends State<TvFocusableCard>
     final isActive = _isFocused || _isHovered;
     final focusColor = widget.focusColor ?? AppColors.primaryContainer;
 
-    return MouseRegion(
+    return Semantics(
+      button: widget.onTap != null,
+      label: widget.semanticLabel,
+      child: MouseRegion(
       onEnter: (_) => _handleHover(true),
       onExit: (_) => _handleHover(false),
       cursor: SystemMouseCursors.click,
@@ -148,6 +155,7 @@ class _TvFocusableCardState extends State<TvFocusableCard>
           ),
         ),
       ),
+      ),
     );
   }
 }