fix(free-tier): setup.ready carries the failure block flat, the shape setup.status already spreads

`SetupRecord.as_payload()` serialised the record verbatim, so the broadcast
nested `failure: {...}` while `setup.status` spread the same four keys flat.
A client keyed on `error_code` saw it on one surface and not the other. Flatten
it in `as_payload`, declare the three optional keys on `SetupReadyPayload`, and
regenerate the TS/OpenRPC contract.

apps/shared/src/gateway-contract.generated.ts

@@ -3838,6 +3838,9 @@ export interface SetupReadyPayload {
   has_identity: boolean
   other_providers: boolean
   error?: string
+  error_code?: string | null
+  retryable?: boolean | null
+  retry_after?: number | null
   finished_at: number
   [key: string]: unknown
 }

apps/shared/src/gateway-contract.openrpc.json

@@ -27293,6 +27293,42 @@
             "title": "Error",
             "type": "string"
           },
+          "error_code": {
+            "anyOf": [
+              {
+                "type": "string"
+              },
+              {
+                "type": "null"
+              }
+            ],
+            "default": null,
+            "title": "Error Code"
+          },
+          "retryable": {
+            "anyOf": [
+              {
+                "type": "boolean"
+              },
+              {
+                "type": "null"
+              }
+            ],
+            "default": null,
+            "title": "Retryable"
+          },
+          "retry_after": {
+            "anyOf": [
+              {
+                "type": "integer"
+              },
+              {
+                "type": "null"
+              }
+            ],
+            "default": null,
+            "title": "Retry After"
+          },
           "finished_at": {
             "title": "Finished At",
             "type": "number"