Fix Qwen3-ASR language option propagation

[0xShug0]

Summary

• Propagate request option language into Qwen3-ASR audio-only requests.
• Preserve Auto as language auto-detection mode.
• Add a CLI request-options regression test for audio-only --language.

Fixes #250

Validation

• cmake --build build/debug --target cli_request_options_test audiocpp_cli -j$(nproc)
• build/debug/bin/cli_request_options_test
• CUDA Qwen3-ASR prompt-token check:
  • no language: qwen3_asr.prompt_tokens 61
  • --language en: qwen3_asr.prompt_tokens 64
  • --language Auto: qwen3_asr.prompt_tokens 61
  • --language zh: qwen3_asr.prompt_tokens 64
  • --language ja: qwen3_asr.prompt_tokens 64
• CUDA --words-out with Qwen3 forced aligner completed and produced word timestamps.
• git diff --check