Links in help output

Print a clickable command name where the terminal understands OSC 8, and a separate URL column only where it does not, deciding the layout with supportsLink().

A help screen with a documentation link per command wants two layouts: on a terminal that understands hyperlinks, the command name itself is the link; everywhere else, the URL has to be printed. supportsLink(runtime) decides the layout, and linkFor(runtime) writes the link.

help.mjs

import { linkFor, supportsLink } from 'paratext/link';

const commands = [
  ['build', 'https://example.dev/docs/build'],
  ['deploy', 'https://example.dev/docs/deploy'],
];

function help(runtime) {
  const link = linkFor(runtime);
  return supportsLink(runtime)
    ? commands.map(([name, url]) => `  ${link(name, url)}`).join('\n')
    : commands.map(([name, url]) => `  ${name.padEnd(8)}${url}`).join('\n');
}

console.log(JSON.stringify(help({ env: { TERM_PROGRAM: 'ghostty' }, isTTY: { stdout: true } })));
console.log(help({ env: {}, isTTY: { stdout: false } }));

node help.mjs

"  \u001b]8;;https://example.dev/docs/build\u0007build\u001b]8;;\u0007\n  \u001b]8;;https://example.dev/docs/deploy\u0007deploy\u001b]8;;\u0007"
  build   https://example.dev/docs/build
  deploy  https://example.dev/docs/deploy

Without supportsLink, the pipe would get build (https://…) from the projection, which is correct but reads worse in a column. paratext/link loads neither the registry nor the schema, so a CLI pays for one capability. flagstaff's boxes and tables render their linked cells through the same capability.