fix: limit SEND_MAIL domain checks to binding paths (#987)

* fix: scope SEND_MAIL domain gating to binding

* test: cover SEND_MAIL domain gating in e2e

e2e/docker-compose.yml

@@ -72,6 +72,24 @@ services:
       start_period: 10s
       retries: 20
 
+  worker-send-mail-domain:
+    build:
+      context: ..
+      dockerfile: e2e/Dockerfile.worker
+      args:
+        WRANGLER_TOML: e2e/fixtures/wrangler.toml.e2e.send-mail-domain
+    ports:
+      - "8791:8791"
+    command: ["pnpm", "exec", "wrangler", "dev", "--port", "8791", "--ip", "0.0.0.0"]
+    depends_on:
+      - mailpit
+    healthcheck:
+      test: ["CMD", "curl", "-sf", "http://localhost:8791/health_check"]
+      interval: 3s
+      timeout: 5s
+      start_period: 10s
+      retries: 20
+
   frontend:
     build:
       context: ..
@@ -128,6 +146,7 @@ services:
       WORKER_URL_SUBDOMAIN: http://worker-subdomain:8789
       WORKER_URL_ENV_OFF: http://worker-env-off:8790
       WORKER_GZIP_URL: http://worker-gzip:8788
+      WORKER_URL_SEND_MAIL_DOMAIN: http://worker-send-mail-domain:8791
       FRONTEND_URL: https://frontend:5173
       MAILPIT_API: http://mailpit:8025/api
       SMTP_PROXY_HOST: smtp-proxy
@@ -146,6 +165,8 @@ services:
         condition: service_healthy
       worker-gzip:
         condition: service_healthy
+      worker-send-mail-domain:
+        condition: service_healthy
       frontend:
         condition: service_started
       smtp-proxy: