v0.4.1

Changes

• Add batch_size to Book.convert().
• Group adjacent narration/dialogue segments into same-style batches.
• Prepare voice conditionals once per batch when voice_path is used, avoiding per-segment voice prompt preparation.
• Document batch_size and add tests for batch grouping and conditional reuse.

Verification

• uv run pytest
• uv build --out-dir /tmp/chatterbook-release-0.4.1