* Fix UTF-8 encoding issue in integrated terminal
- Set LANG and LC_ALL environment variables to en_US.UTF-8
- Resolves Encoding::CompatibilityError in Ruby/CocoaPods commands
- Ensures consistent UTF-8 encoding across all terminal sessions
This change addresses the terminal encoding issue where commands like
'pod install' would fail due to incompatible character encoding. The
fix ensures all integrated terminals are initialized with proper
UTF-8 locale settings.
* Add comprehensive unit tests for ExecaTerminalProcess UTF-8 encoding fix
- Tests verify LANG and LC_ALL are set to en_US.UTF-8
- Tests ensure existing environment variables are preserved
- Tests confirm UTF-8 settings override conflicting locale values
- Addresses PR feedback requesting test coverage for encoding fix
- All 7 tests passing with proper mocking of execa and ps-tree
