render ignores the first H1: untitled sources all publish to the slug 'artifact' and silently overwrite each other

[bitgorust]

Summary

opencode-artifacts render <file.md> sets the title to the literal string Artifact
when the source has no frontmatter title:. It ignores the first # heading. The slug
becomes artifact, so every untitled source publishes to the same page.

Two different documents therefore collapse into one artifact, and the first one is lost
without a warning.

Reproduction

printf -- '# Alpha Report\n\nFirst doc.\n' > a.md
printf -- '# Beta Report\n\nSecond doc.\n' > b.md
npx opencode-artifacts@0.14.4 render a.md
npx opencode-artifacts@0.14.4 render b.md

ls .opencode/artifacts          # artifact.html, index.html, manifest.json
grep -o 'First doc\.' .opencode/artifacts/artifact.html   # no match
grep -o 'Second doc\.' .opencode/artifacts/artifact.html  # match

manifest.json holds a single entry: {"slug": "artifact", "title": "Artifact"}.

Expected

Fall back to the first # heading before falling back to Artifact. For the example
above that gives slug alpha-report and title Alpha Report, and the two documents stay
separate.

Why it matters

• The naming rule in skills/artifact-pages/SKILL.md says to name the page like a product.
  A CLI user who follows normal Markdown practice, one # heading per document, cannot
  reach that outcome.
• The overwrite is silent. publish() keys on slug, so the second render replaces the
  stable page of the first.
• The heading is already parsed; the information needed for a better default is present.

Source

dist/cli.js, renderCommand:

const finalTitle = title ?? rendered.meta.title ?? "Artifact";

Environment

opencode-artifacts 0.14.4, Node v24.19.0, OpenCode 1.18.9, macOS 25.5.0.