refactor(translator): configure max_tokens from config, enhance error messages

- Read max_tokens from config.yaml (output.naming.languages.{lang}.translator_max_tokens)
- Remove hardcoded max_tokens logic
- Add comprehensive request details to all error messages
- Include model, prompt size, tokens, content size in error output
- Add configuration documentation in code comments and README
- Emphasize checking debug output files for full request/response details

Author: lufftw