feat: TOC block, Goal Seek, table slides, timezone, forms export & piping (0.44.0)
Cross-editor feature batch:
- Docs: auto-updating Table of Contents block with live refresh (#651)
- Docs: 4 new templates (Technical Spec, Letter, Journal, Knowledge Base) (#653)
- Sheets: Goal Seek solver (secant + bisection fallback) (#655)
- Slides: rich table rendering from PPTX import (#659)
- Calendar: per-event IANA timezone with abbreviation display (#660)
- Forms: CSV/Excel response export (#664)
- Forms: answer piping with {{Q1}} placeholders (#665)
- Fix: TOC HTML entity double-encoding bug
62 new tests, 8601 total passing.