Replace offline cache with network-based Codex setup

- Remove large split archive files and offline cache setup
- Add setup_for_codex.sh script that uses network during setup
- Add clean_codex_cache.sh to remove any remaining cache files
- Update CODEX_WORKFLOW.md with network-based setup instructions
- Add AGENTS.md with guidance for AI development
- Add Codex-specific gitignore

Author: Jenner Torrence

.codex/.gitkeep

@@ -0,0 +1,78 @@
+# Flutter/Dart specific ignores
+.dart_tool/
+.flutter-plugins
+.flutter-plugins-dependencies
+.packages
+.pub-cache/
+.pub/
+build/
+generated_plugin_registrant.dart
+
+# Android related
+**/android/.gradle
+**/android/captures/
+**/android/local.properties
+**/android/**/GeneratedPluginRegistrant.java
+
+# iOS/XCode related
+**/ios/**/*.mode1v3
+**/ios/**/*.mode2v3
+**/ios/**/*.moved-aside
+**/ios/**/*.pbxuser
+**/ios/**/*.perspectivev3
+**/ios/**/*sync/
+**/ios/**/.sconsign.dblite
+**/ios/**/.tags*
+**/ios/**/.vagrant/
+**/ios/**/DerivedData/
+**/ios/**/Icon?
+**/ios/**/Pods/
+**/ios/**/.symlinks/
+**/ios/**/profile
+**/ios/**/xcuserdata
+**/ios/.generated/
+**/ios/Flutter/App.framework
+**/ios/Flutter/Flutter.framework
+**/ios/Flutter/Flutter.podspec
+**/ios/Flutter/Generated.xcconfig
+**/ios/Flutter/app.flx
+**/ios/Flutter/app.zip
+**/ios/Flutter/flutter_assets/
+**/ios/Flutter/flutter_export_environment.sh
+**/ios/ServiceDefinitions.json
+**/ios/Runner/GeneratedPluginRegistrant.*
+
+# macOS
+**/macos/Flutter/GeneratedPluginRegistrant.swift
+**/macos/Flutter/Flutter-Debug.xcconfig
+**/macos/Flutter/Flutter-Release.xcconfig
+**/macos/Flutter/Flutter-Profile.xcconfig
+
+# Symbolication related
+app.*.symbols
+
+# Obfuscation related
+app.*.map.json
+
+# Android Studio will place build artifacts here
+**/android/app/debug
+**/android/app/profile
+**/android/app/release
+
+# Codex offline cache directories
+# We don't need these anymore as we use network during setup
+.codex/flutter-sdk/
+.codex/pub-cache/
+.codex/flutter-sdk.tar.gz
+.codex/pub-cache.tar.gz
+.codex/flutter-sdk.tar.gz.part.*
+.codex/pub-cache.tar.gz.part.*
+.codex/reassemble.sh
+.codex_setup_complete
+
+# Temporary files
+*.log
+*.tmp
+.DS_Store
+*.swp
+*.bak