feat(billing): implement tenant subscription entitlements system (milestones 0-6)

runner/config/effects.prod.yaml

@@ -0,0 +1,27 @@
+effects:
+  - name: noop
+    provider: noop
+    config: {}
+  - name: send_email
+    provider: email
+    config:
+      # Choose ONE backend for production.
+      #
+      # Option A) SMTP (recommended when you have an SMTP relay):
+      backend: smtp
+      url_env: RUNNER_SMTP_URL
+      #
+      # Option B) Resend:
+      # backend: resend
+      # api_key_env: RESEND_API_KEY
+      # from: "no-reply@example.com"
+      #
+      # Option C) Postmark:
+      # backend: postmark
+      # server_token_env: POSTMARK_SERVER_TOKEN
+      # from: "no-reply@example.com"
+      #
+      # Option D) AWS SES:
+      # backend: ses
+      # region: "eu-central-1"
+      # from: "no-reply@example.com"

runner/config/effects.yaml

@@ -2,3 +2,8 @@ effects:
   - name: noop
     provider: noop
     config: {}
+  - name: send_email
+    provider: email
+    config:
+      backend: smtp
+      url_env: RUNNER_SMTP_URL