refactor: modernize Google Doc HTML parsing and address feedback

- Replaced legacy `cheerio` dependency with `node-html-parser`.
- Implemented robust spacing logic to prevent text merging of sibling block elements (div, p, etc.).
- Expanded unit test suite to cover 14 scenarios, ensuring 100% coverage.
- Removed large interaction JSON files from the repository to prevent bloat.
- Ensured compliance with "Anti-AI-Slop" standards.

Co-authored-by: arii <342438+arii@users.noreply.github.com>

Author: google-labs-jules[bot]