- Fenced code blocks with diff/patch lang hint render with colored lines
(green +lines, red -lines, italic @@ hunks)
- MEDIA:.patch/.diff files render inline instead of download link
(async fetch via loadDiffInline() in post-render pipeline)
- CSS: diff-block, diff-line, diff-plus/minus/hunk classes
- i18n: diff_loading key in all 7 locales
- 12 tests: renderer, MEDIA inline, CSS classes, i18n parity
Closes#483