Add a scraper

Follow CONTRIBUTING.md and the repository’s create-scraper skill. That workflow inspects the board in a browser, finds its underlying JSON API and implements a subclass.

The public Scraper contract includes listing/full-content methods, URL parsing and optional discovery capabilities. Declare whether slugs can be derived from names; Workday-style identities should not be probed as guessed names. Keep company-owned domains distinct from shared board hosts.

Use Bun for development, bun run test for the isolated source-condition test runner, and source execution with bun --conditions=job-scraper-source <file>. Published code must remain plain ESM compatible with Node 22+, Bun, Deno and browsers; Bun-only APIs belong in tests/dev scripts.