Add typedoc and typedoc-plugin-markdown as devDependencies. Add typedoc.json config
targeting src/index.ts with markdown output to .github/wiki/api. Add docs script to
package.json. Generate initial API reference pages.
Part of T-E8-03 — TypeDoc automation for all 12 JS/TS packages.
Day.js plugin adding Hijri calendar support via hijri-core. Adds
toHijri(), fromHijri(), hijriYear/Month/Day(), isValidHijri(), and
formatHijri() to all Day.js instances. Supports UAQ and FCNA calendars
via ConversionOptions. Format token escaping wraps substituted values
in Day.js bracket syntax to prevent re-interpretation as format tokens.
14 ESM + 8 CJS tests passing. Dual CJS/ESM build.
