Split REVIEW_MAX_COMMENTS into two independent variables:
- REVIEW_MAX_COMMENTS: total comments per PR (context review)
- REVIEW_MAX_INLINE_COMMENTS: comments per file (inline review)
Addresses AI reviewer feedback for independent configuration.
REVIEW_MAX_COMMENTS was only mapped to REVIEW__MAX_INLINE_COMMENTS which
only limits comments per-file. Added REVIEW__MAX_CONTEXT_COMMENTS mapping
to also limit total comments per MR, which is what users expected.
Also added missing LLM__META__TEMPERATURE env var mapping.