feat(multi-turn-bench): add api_key and custom headers for multi turn benchmark

[jimmy-evo]

Purpose

add args api-key custom-header for multi-turn benchmark.

add validation for "no-chunk" stream requests: stream request with no ttft counted.

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[mergify]

Hi @jimmy-evo, the pre-commit checks have failed. Please run:

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[mergify]

This pull request has merge conflicts that must be resolved before it can be
merged. Please rebase the PR, @jimmy-evo.

https://docs.github.com/en/pull-requests/collaborating-with-pull-requests/working-with-forks/syncing-a-fork

[depthfirst-app]

⚪ Severity: LOW

The --api-key argument value will be logged in plaintext at line 1533 (logger.info(args)), which dumps the entire args namespace including api_key. This exposes the bearer token/secret credential in log output.
Helpful? Add 👍 / 👎

💡 Fix Suggestion

Suggestion: Redact the api_key field before logging the args namespace at line 1533. You can either:

1. Create a sanitized copy of the args for logging: replace logger.info(args) with code that masks or removes the api_key value before printing, e.g.:

   args_to_log = vars(args).copy()
   if args_to_log.get('api_key'):
       args_to_log['api_key'] = '***REDACTED***'
   logger.info(args_to_log)

2. Or simply omit the full args dump and rely on the individual parameter logging that follows it.