feat(server): hide language probabilities option behind flag

[sachaarbonel]

Add language probabilities feature flag to reduce latency

Adds a feature flag to make language probabilities optional in the verbose JSON output format. Computing language probabilities is an expensive operation that adds considerable latency to responses.

Changes:

• Added language_probabilities boolean flag (default: true)
• Added CLI flags: -nlp, --no-language-probabilities
• Added HTTP parameter: no_language_probabilities
• Modified JSON response to conditionally include probabilities

Usage

Command line:

# Disable language probabilities for faster response
./server --model models/ggml-base.en.bin -nlp

HTTP API:

curl 127.0.0.1:8080/inference \
  -F file="@audio.wav" \
  -F response_format="verbose_json" \
  -F no_language_probabilities="true"

[sachaarbonel]

@danbev thanks for your reviews, I applied them. Can you check again