BookWyrm: update Dockerfile and env handling

- Remove ARG BOOKWYRM_VERSION default, use Jinja variable directly
- Add proper SMTP environment variables mapping (EMAIL_HOST, EMAIL_PORT, TLS/SSL flags, user, password, default_from)
- Ensure env.j2 uses BookWyrm-expected names only
Ref: ChatGPT conversation 2025-09-02 https://chatgpt.com/share/68b6dc73-3784-800f-9a7e-340be498a412

roles/web-app-bookwyrm/templates/env.j2

@@ -11,7 +11,15 @@ ALLOW_INVITE_REQUESTS={{ BOOKWYRM_ALLOW_INVITE_REQUESTS }}
 
 # Django/Secrets (provide via vault/env in production)
 SECRET_KEY="{{ BOOKWYRM_SECRET_KEY }}"
-EMAIL="{{ users['no-reply'].email }}"
+
+# Email / SMTP (BookWyrm expects these names)
+EMAIL_HOST="{{ EMAIL_HOST }}"
+EMAIL_PORT="{{ EMAIL_PORT }}"
+EMAIL_USE_TLS={{ EMAIL_USE_TLS }}
+EMAIL_USE_SSL={{ EMAIL_USE_SSL }}
+EMAIL_HOST_USER="{{ EMAIL_HOST_USER }}"
+EMAIL_HOST_PASSWORD="{{ EMAIL_HOST_PASSWORD }}"
+DEFAULT_FROM_EMAIL="{{ EMAIL_DEFAULT_FROM }}"
 
 # Database
 DATABASE_URL="postgres://{{ database_username }}:{{ database_password }}@{{ database_host }}:{{ database_port }}/{{ database_name }}"