Add a minimal payment mock server for end-to-end testing

docker-compose.e2e.yaml

@@ -105,6 +105,31 @@ services:
       timeout: 3s
       retries: 10
 
+  # Stand-in for the payment microservice. The API's reconcile-before-expire
+  # step (booking-batch.service.ts:3492) asks the gateway whether a late
+  # payment landed before it will expire an unpaid hold, and treats ANY error
+  # as "unverifiable" — which defers the expiry forever. PAYMENT_API_URL
+  # otherwise defaults to the real paymentcallback.triaplc.com, unreachable
+  # from here, so without this every expiry scenario hangs. See
+  # payment-mock/server.js.
+  payment-mock-e2e:
+    image: node:20-alpine
+    volumes:
+      - ./e2e/freight/payment-mock:/app:ro
+    working_dir: /app
+    command: ["node", "server.js"]
+    healthcheck:
+      test:
+        [
+          "CMD",
+          "node",
+          "-e",
+          "fetch('http://localhost:4500/health').then(r=>process.exit(r.ok?0:1)).catch(()=>process.exit(1))",
+        ]
+      interval: 3s
+      timeout: 3s
+      retries: 10
+
   # Stand-in for https://etrade.gov.et — ETradeService's base URL is
   # hardcoded (not env-configurable like Fayda's endpoints), so this is
   # reached by DNS alias instead: the "etrade.gov.et" network alias below
@@ -166,6 +191,8 @@ services:
         condition: service_healthy
       etrade-mock-e2e:
         condition: service_healthy
+      payment-mock-e2e:
+        condition: service_healthy
     environment:
       PORT: "3001"
       DB_HOST: postgres-freight-e2e
@@ -202,6 +229,10 @@ services:
       FAYDA_ENABLED: "true"
       FAYDA_CLIENT_ID: e2e-fayda-client
       FAYDA_AUTHORIZATION_ENDPOINT: http://fayda-mock-e2e:4400/authorize
+      # Without this the payment client calls the real (unreachable)
+      # paymentcallback.triaplc.com and every unpaid hold defers instead of
+      # expiring — see payment-mock/server.js.
+      PAYMENT_API_URL: http://payment-mock-e2e:4500
       FAYDA_TOKEN_ENDPOINT: http://fayda-mock-e2e:4400/token
       FAYDA_USERINFO_ENDPOINT: http://fayda-mock-e2e:4400/userinfo
       FAYDA_REDIRECT_URI: http://localhost:${E2E_PORTAL_PORT:-5373}/callback