Fix gemini cli command parsing

[katzdave]

Summary

OS string causing problems and not actually looking at the environment variable.

[Copilot]

Pull request overview

This PR fixes command parsing for CLI-based providers by changing the configuration value type from OsString to String.

Changes:

• Updated config macro to use String instead of OsString for command configuration values (GEMINI_CLI_COMMAND, CURSOR_AGENT_COMMAND, CODEX_COMMAND, CLAUDE_CODE_COMMAND)
• Modified all four CLI providers to use String type and pass commands by reference to SearchPaths::resolve()
• Removed unnecessary OsString imports from all affected files

Reviewed changes

Copilot reviewed 5 out of 5 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
crates/goose/src/config/base.rs	Changed config_value! macro declarations from OsString to String for all four command configs
crates/goose/src/providers/gemini_cli.rs	Updated to use String type and pass command by reference, removed OsString import
crates/goose/src/providers/cursor_agent.rs	Updated to use String type and pass command by reference, removed OsString import
crates/goose/src/providers/codex.rs	Updated to use String type and pass command by reference, removed OsString import
crates/goose/src/providers/claude_code.rs	Updated to use String type and pass command by reference, removed OsString import