Draft 0.2.0-alpha.4 — A quieter caret

The editor now uses a thin insertion caret matched to the height of the text, including headings and blank lines. The landing page walkthrough uses the same thinner caret.

Includes the latest responsive walkthrough and live window resizing fixes.

Validation: 44 tests passed; renderer, website, and macOS builds passed. Installed on macOS and checked visually, with existing documents and alternatives preserved.

Apple Silicon · macOS 13 or later. Early alpha, ad-hoc signed and not notarized.