Font family & size controls for editor #10
Description
Summary
Allow setting font family and size via View → Font sub-menu.
Tasks
- Add menu with common fonts (Monospace, Serif, Sans) and sizes (12, 14, 16, 18).
- Apply via
txtarea.setStyle("-fx-font-family: ...; -fx-font-size: ...;"). - Persist last choice (optional).
Acceptance Criteria
- Selection immediately updates editor font.