Per the Nexedi RenderJS gadget guidelines (GUIDE-RJS-001..006):
- .then() -> RSVP.Queue .push() (also fixes a missing `new
  RSVP.Promise` and a .push() called on a native Promise in
  crib-enable.js)
- bare fetch() -> jIO.util.ajax with dataType blob/json
  (landing + import; GitHub API errors read error.target.status)
- setTimeout -> RSVP.delay (one documented exception:
  gadget_global postMessage primitive with cleanup race)
- raw addEventListener -> loopEventListener / event delegation in
  declareService (url_list delete-confirm, compare row clicks,
  editor preview/shortcuts, launcher postMessage loop; documented
  exceptions: error-display button, SW statechange one-shot bridge)
- DOM ids -> classes (editor, select_site; datalist id kept for
  the required <input list=> pairing, documented)
- index.html script order rsvp -> renderjs -> jio
- codemirror gadget getContent/getSupportedTypeList wrapped in
  RSVP.Queue; /*global*/ + IIFE header trios completed everywhere
- editor URL-suggestions datalist: fix pre-existing data-shape bug
  (crib_sw_allDocs returns a url dict, not {data:{rows}})

Verified live on cribjs.nexedi.net: 25/25 smoke checks, QUnit
48 tests / 113 assertions green.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>