The edge answers when the forge does not: a static "the forge is restarting" page and the last Resilience page, served by the Worker itself #1194

Part of #1148 (failure domain: compute). Today infra/forge-cloudflare/worker.js answers a request the body cannot take with a plain-text 502, and only /healthz is answered by the edge.

Done looks like:

• [ ] src/cloud/edge.ts renders one self-contained HTML page (no script, inline style, the CSP floor) saying the forge is restarting and when the edge last heard from it; the Worker serves it with 503 and Retry-After for any GET a browser makes while the body is unreachable.
• [ ] The Worker keeps a copy of the last Settings → Resilience map (pushed by the forge on boot and when it changes) and serves it at /settings/resilience when the body is down, marked as a copy and its age.
• [ ] A test runs the Worker's fetch with an unreachable body and asserts both pages; nothing else the edge does changes.

Parked by the crew: the check failed ("the gate's list > every test/*.test.ts is in exactly one list, and every entry exists") and the decider saw no point in another try (pull #1203 closed). Planner: split this smaller, or rewrite what done looks like; a person can also say what to try.

Parked by the crew: the check failed ("the gate's list > every test/*.test.ts is in exactly one list, and every entry exists") and the decider saw no point in another try (pull #1484 closed).

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

1. the check failed ("the gate's list > every test/*.test.ts is in exactly one list, and every entry exists") and the decider saw no point in another try (pull #1203 closed)
2. the check failed ("the gate's list > every test/*.test.ts is in exactly one list, and every entry exists") and the decider saw no point in another try (pull #1484 closed)

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.

Deferred behind the Later gate (#595): the edge fallback page waits behind /flow and Boards. Both pulls went red on the gate's list: when it comes back, put the new test file in GATE in scripts/gate.ts.