feat: rename api_key to token for consistency with BUDDY_TOKEN output

[shipurjan]

PR Description

Summary

Renames the api_key input parameter to token throughout the codebase to maintain consistency with the BUDDY_TOKEN environment variable that the action exports.

Why this change?

The action was using api_key as an input parameter but exporting it as BUDDY_TOKEN to the environment. This naming inconsistency could cause confusion. By renaming the input to token and clarifying it as a PAT (Personal Access Token), we create a more intuitive and consistent API.

What changed?

• Input parameter: api_key → token
• Output parameter: api_key → token
• Documentation: Updated to clarify "PAT (Personal Access Token)"
• Type definitions: All TypeScript interfaces and types updated
• Error messages: Updated to use "token" terminology
• README: Corrected required field indicators and updated examples

Breaking Change

This is a breaking change for users currently using the api_key input parameter. They will need to update their workflows to use token instead of api_key.

Migration Guide

1. Update your workflow files to use token instead of api_key
2. Consider renaming your GitHub secret from BUDDY_API_KEY to BUDDY_PAT for clarity
3. If consuming the output, update from steps.buddy_login.outputs.api_key to steps.buddy_login.outputs.token