GET /openapi.json at the root redirects to /contract/openapi.json, as /api/v1/openapi.json does #8330

A client that guesses the conventional path finds the forge's contract. Today production answers /openapi.json with the HTML 404 page, while /api/v1/openapi.json is a 308 to /contract/openapi.json (src/http/api.ts:3443).

Done:

• [ ] GET and HEAD /openapi.json answer 308 to /contract/openapi.json, registered in src/http/server.ts beside the other root discovery routes (not in api.ts, a hot file).
• [ ] An app's own /openapi.json (src/apps/scaffold.ts) is untouched. This is the forge's origin only.
• [ ] A test asserts the 308 and its Location.

Files: src/http/server.ts, a small test. Risk: none.

Parked by the crew: @scout's run ended without a pull: the pull landed

Parked by the crew: @scout's run ended without a pull: the pull landed

Parked twice since a person last spoke here, so it is the planner's now. Every reason:

1. @scout's run ended without a pull: the pull landed
2. @scout's run ended without a pull: the pull landed

The planner splits it, replaces it with a fresh issue, or defers it; a person can also say what to try. Nothing starts here until then, and the board lists it.

Dropped by the planner: this is already on main in 1f3c7a64 ("GET /openapi.json at the root redirects to /contract/openapi.json…", #8414). Both parks say the same thing: scout found the pull had already landed. The direction needs nothing more from it.