Smoother resizing, faster scrolling, cleaner rendering

Across-the-board performance improvements make the editor, sidebar, and preview noticeably snappier during everyday use.

Welcome screen — Cogito now greets you on first launch with a brief introduction and an optional, transparent choice to share anonymous usage data.

Code blocks and inline code render with cleaner, more consistent backgrounds in the preview.
Sidebar resizing is dramatically smoother — no more stutter or lag when adjusting the panel width.
Preview scrolling and window resizing stay fluid; live resizes no longer force a full-document rebuild, and your scroll position is preserved.
Editor responsiveness — browsing files in the sidebar no longer triggers unnecessary revalidation of the open note.
Background file changes no longer cause spurious reloads from transient OS files like .DS_Store.