[UI/UX] Implement Global UX Rules - Mini Player Visibility

[ucguy4u]

Part of #187

Overview

Implement global UX rules to prevent cross-tab UI pollution.

Required Changes

• Mini players only visible on Beats (index 2) and Stream (index 3) tabs
• Create MiniPlayerVisibility provider
• Update AppShell _ContextAwareMiniPlayers logic
• Audit all tabs to ensure no cross-tab pollution
• Verify quotes only appear in Mind tab
• Verify greetings only appear in Mind tab
• Remove DailyQuoteCard from money_overview_screen.dart

Files

• app/lib/core/app/app_shell.dart
• app/lib/features/money/presentation/screens/money_overview_screen.dart
• app/lib/features/music/presentation/widgets/mini_player.dart
• app/lib/features/iptv/presentation/widgets/iptv_mini_player.dart