fix(relay-ops): let the rehome trust probe approve the asia-east2 cells (#19275)

cloud/dev/scripts/probe-relay-rehome-trust.mjs

@@ -1,7 +1,9 @@
 import { pathToFileURL } from 'node:url'
 import { fetchAdminOnceMore } from './relay-admin-transient-retry.mjs'
 
-const PRODUCTION_CELL = /^production-gce-c(?:7|8|9|10|13|14|15|16|19|20|21|22|23|24|25|26)$/
+// Every general cell that carries the rehome identity: the sixteen US cells and the
+// three asia-east2 cells that drain mis-homed hosts back the other way.
+const PRODUCTION_CELL = /^production-gce-c(?:7|8|9|10|13|14|15|16|19|20|21|22|23|24|25|26|27|28|29)$/
 const DIRECTOR_ORIGIN = 'https://relay.onorca.dev'
 
 export function parseRehomeTrustProbeArguments(argv, environment = process.env) {

cloud/dev/scripts/probe-relay-rehome-trust.test.mjs

@@ -111,3 +111,23 @@ test('fails when both trust-probe attempts return a transient 503', async () =>
   )
   assert.equal(calls, 2)
 })
+
+test('approves the asia-east2 rehome sources and still rejects unlisted cells', () => {
+  for (const cellId of ['production-gce-c27', 'production-gce-c28', 'production-gce-c29']) {
+    const parsed = parseRehomeTrustProbeArguments(
+      argv.map((value) => (value === 'production-gce-c7' ? cellId : value)),
+      environment
+    )
+    assert.equal(parsed.cellId, cellId)
+  }
+  for (const cellId of ['production-gce-c1', 'production-gce-c17', 'production-gce-c30']) {
+    assert.throws(
+      () =>
+        parseRehomeTrustProbeArguments(
+          argv.map((value) => (value === 'production-gce-c7' ? cellId : value)),
+          environment
+        ),
+      /--cell-id is not approved/
+    )
+  }
+})