[UI/UX] Update Bottom Navigation to 6-Tab Structure

[ucguy4u]

Part of #187

Overview

Update navigation structure from current 5 tabs to new 6-tab layout.

New Tab Structure

1. Coins -> /money (MoneyOverviewScreen)
2. Mind -> /mind (MindScreen) - NEW
3. Beats -> /music (MusicScreen)
4. Stream -> /iptv (IPTVScreen)
5. Arena -> /games (GamesHubScreen)
6. Quest -> /quest (QuestListScreen)

Required Changes

• Update app_router.dart with 6 StatefulShellBranch entries
• Update navigation_provider.dart standardModeTabs to 6 tabs
• Update app_shell.dart for new tab indices
• Update initial route to /money

Files

• app/lib/core/routing/app_router.dart
• app/lib/core/providers/navigation_provider.dart
• app/lib/core/app/app_shell.dart