Render dev disaster bodies as markdown, not plain paragraphs

[michaeljolley]

What

Dev disaster story bodies were split on blank lines into paragraphs and drawn as plain text. Any markdown typed into the submit form (bold, links, code fences) came through literally instead of being rendered.

Why

Comments already had a safe markdown renderer in src/lib/markdown.ts - built from marked's token stream with an allow list of eight tags, headings demoted to bold paragraphs, and code fences highlighted through shiki. There was no reason for a disaster body to have a second, weaker renderer, so it now goes through the same one.

Changes

• Disaster.body is now a rendered HTML string instead of string[] paragraphs.
• paragraphs() is gone; renderBody() takes its place and calls renderComment from src/lib/markdown.ts.
• shapeDisasters is now async, since rendering a body is.
• The dev disaster page renders the body with set:html instead of mapping paragraphs.
• Tests updated to cover markdown rendering (bold text, heading demotion) instead of the old paragraph-splitting behavior.

Testing

• pnpm test - all 379 tests pass
• pnpm check - 0 errors, 0 warnings
• pnpm build - succeeds, pnpm check:dist clean

Co-authored-by: Copilot App 223556219+Copilot@users.noreply.github.com