Format code reviews with severity flags

Convert markdown code-review to 2-column HTML

Single-file PR reviews with margin annotations and severity breakdowns.

• · Markdown with ```diff blocks and > [!SEVERITY] callouts

• · Single-file HTML with jump-nav, unified diff, severity annotations

• · Python 3 (diff_parser, annotation_extractor, review_html_renderer)

• · Input must contain ``` diff ``` blocks and severity callouts
• · Markdown >= 100 lines
• · Design-system onboarded
• · --reviewer flag mandatory

• · Exit 3: no --reviewer flag
• · Exit 4: no diff hunks found
• · Exit 5: input < 100 lines
• · Severity-only-color rejected by WCAG

• · WCAG 1.4.1 enforcement (color + icon + aria-label)
• · Signed by Alireza Rezvani, MIT licensed
• · Complies with Google Code Review Developer Guide