Pup - Puppeteer Bridge

DEFERRED FEATURE, recorded so it is not forgotten (John 2026-08-10: "leave move-to-webview as a future TODO, not enough value add right now").

The design is complete in docs/PLAN-interactive-surface.md (Phase 3) and the exploration is done:

• ah (local Hydrogen): buildable with ZERO new ab verbs. pup -> ab SDK callback -> hd_api {port:47083, POST /api/workspaces/editor/local/workspace/current/tabs} with the webview panelType + initialState.url, open-or-refresh semantics, then close the pup window. Endpoint defaults from the window's recorded caller container.
• hc (cloud): desktop -> hydrogen.adom.inc workspace API over public HTTPS (slug -> owner/repo via carbon lookup). ONE blocker: whether ab's Adom Cloud session token is accepted for workspace mutations (else only the container-mounted api-key works). Surface the E2 409 honestly; rewrite localhost URLs to the slug proxy (SSRF guard).
• Nice-to-have ab asks when revived: hydrogen_endpoints (union of ah + connected hc with owner/repo/liveness) and hydrogen_open_webview {endpoint,url,name}; mirror Browser Picker destination ids so hbw's move-to-surface and pup's are one concept.
• UI when revived: "Move to my workspace" row in the toolbar popup + jump list.

Also deferred in the same plan: push-back-to-container via a new ab container_deliver verb (the annotation return path currently rides the clipboard; the ready-to-paste ab prompt is in the plan's Phase 2 section).