Extract the unified-diff parser into UnifiedDiffParser and the styled line renderer into a reusable DiffLinesView control. The combined (planning) diff now parses its unified-diff string and renders color-coded rows (green additions / red deletions, file headers) identical to the per-task viewer instead of dumping plain text into a TextBox. Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>