Obsidian plugin review fixes
- Removed blocked lint suppression comments for TTS commands and kept command labels review-safe.
- Replaced direct textarea style assignment with CSS class and CSS custom properties.
- Cleaned up popout-window compatibility issues, redundant type assertions, unsafe array spreads, Node builtin imports, and TFile/TFolder casts flagged by plugin review.
- Bumped plugin metadata to 3.9.1.