This commit adds the `checkGitRepository` function to the `helpers.js` module which checks if the current directory is a Git repository using the `git rev-parse --is-inside-work-tree` command. If it's not a Git repository, an error message will be logged to the console and the process will exit with code 1. The `checkGitRepository` function is exported from the module along with the `getArgs` function.

Additionally, this commit modifies the `index.js` module to import `checkGitRepository` from `helpers.js`. The `generateAICommit` function now calls `checkGitRepository` before executing the `git diff --staged` command and logs an error message if it returns false.