Add a --temperature flag (default 0)

[Cyberfilo]

PromptQuery runs the LLM at temperature=0 for determinism (see src/promptquery/llm.py). Expose this as a CLI flag --temperature (Click option on cli.py), defaulting to 0, threaded into the generate() calls. Keep 0 the default so behaviour is unchanged unless asked.

Good first issue: touches cli.py + llm.py, no new deps.

[Priyansh2116]

Hi! I'd like to work on this. Planning to add a --temperature Click option (default 0) to cli.py and thread it into both AnthropicClient and OpenAIClient via make_client(). Will open a PR shortly.