Fetches a URL, builds the heading outline (H1 → H6), flags missing H1, multiple H1s, skipped levels (H2 → H4), and headings without text. Outputs a paste-ready table-of-contents block.
Fetches a URL, walks every <h1> through <h6>, and renders the full outline. Flags missing H1, multiple H1s, skipped levels (e.g. H2 → H4), and headings without text. Outputs a paste-ready table-of-contents block.