feat: report detailed token usage metrics in action outputs and logs

[appleboy]

• Add token usage metrics (prompt_tokens, completion_tokens, total_tokens) to action outputs and documentation
• Output additional details if available, such as cached prompt tokens, reasoning tokens, accepted/rejected prediction tokens
• Update action to print detailed token usage information in the logs

[Copilot]

Pull request overview

This PR adds comprehensive token usage metrics to the GitHub Action's outputs and logs, enabling users to track and monitor token consumption for cost optimization and usage analysis.

Key Changes:

• Add core token usage metrics (prompt_tokens, completion_tokens, total_tokens) to action outputs
• Include optional detailed metrics (cached tokens, reasoning tokens, accepted/rejected prediction tokens) when available from the API
• Add formatted token usage information to action logs for visibility during execution

Reviewed changes

Copilot reviewed 5 out of 5 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
main.go	Implements token usage logging and adds token metrics to GitHub Actions outputs with proper nil checks for optional fields
action.yml	Defines new output parameters for token usage metrics with clear descriptions
README.md	Documents the new token usage output parameters with explanations of when optional fields are available
README.zh-CN.md	Chinese (Simplified) translation of the token usage output documentation
README.zh-TW.md	Chinese (Traditional) translation of the token usage output documentation

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