A preview of the forge can be looked at as its owner: looks of chosen pages are taken signed in, over seeded data #8812

The screenshot boxes on #8698 (/flow) and #8726 (home's pins) could not be met. Looks of a public app on a public repository are taken signed out (src/looks/service.ts, asNobody), and a preview of the forge itself starts empty. So every owner-only page looks blank to a reviewer.

Done looks like:

• [x] forge.json can name pages to look at as the owner (for example /, /flow, /talk). For those, the desk and phone looks are taken signed in as a preview-only admin.
• [x] A preview of the forge seeds that admin and a small fixture: a repository with issues, a pull, pins and a flow week. It exists only in previews, never in production, and its session is never shown or logged.
• [ ] The first pull carries desk and phone looks of home with pins and of /flow. Those are the boxes #8698 and #8726 left.
• [x] Tests: the seed runs only when the environment is a preview; a look listed as owner carries the admin grant; one not listed is still taken as nobody.

Files: src/looks/service.ts, src/apps/manifest.ts (forge.json looks), a preview seed module beside src/spawn, forge.json, test/looks-owner.test.ts (new) Risks: a seeded admin reaching production. Gate it on the preview environment the runtime sets, and test that production refuses it.

Reviewed pull #8830 at its head: ticked forge.json can name pages to look at as the owner (for example /, /flow, /talk). For those, the desk and phone looks are taken signed in as a preview-only admin.; A preview of the forge seeds that admin and a small fixture: a repository with issues, a pull, pins and a flow week. It exists only in previews, never in production, and its session is never shown or logged.; Tests: the seed runs only when the environment is a preview; a look listed as owner carries the admin grant; one not listed is still taken as nobody.. left open: The first pull carries desk and phone looks of home with pins and of /flow. Those are the boxes #8698 and #8726 left. — The parent forge runs main and ignores looksAsOwner until this merges, so this pull carries no such looks; the next pull will..

Left open after pull #8830 landed: 1 unticked item remains (The first pull carries desk and phone looks of home with pins and of /flow. Those are the boxes #8698 and #8726 left.). The planner files each as its own issue and closes this one; a person may close it, tick what is done, or say what is left. Until then the crew does not pick it again.

The open box (looks of home with pins and of /flow) is now part of #8865. The forge takes those looks on any forge pull's preview now that #8830 landed, and #8865 adds a test that fails if either page renders blank for the preview owner.