v0.2.83

Added

• MarkdownContentView — new shared SwiftUI component for rendering markdown previews with fenced code block support (monospace font, background), inline formatting, and heading styles
• Version history comparison mode improvements — sidebar deltas now respond to "vs Current / vs Previous" picker; per-section word deltas shown in backup column; new sections show full count as positive delta

Changed

• Version history redesign — redesigned version history window and sheet with improved layout: matched header button heights (.bordered/.small), increased header breathing room, tightened section row spacing (VStack 8→4, vertical padding 8→6), hidden redundant Filter label
• Build process — updated build process so Chrome always loads; added build phases in project.yml
• Documentation reorganized — split monolithic lesson files into focused sub-files with INDEX.md navigation; cleaned up old plans; restructured editor communication docs

Fixed

• Unstable SwiftUI IDs — MarkdownElement.lineBreak now carries a stable index instead of generating a new UUID on every access, which defeated SwiftUI diffing
• O(n²) snapshot list performance — SnapshotRowView now receives precomputed snapshotIndex via lookup map, eliminating O(n) firstIndex(where:) per row
• Duplicated backup analysis — extracted computeBackupAnalysis() shared helper, eliminating duplication between Window and Sheet views