Enhance emulator setup with Caddy support and update documentation

- Added Caddyfile example for HTTPS configuration.
- Updated README to include Caddy as an optional component.
- Modified make-certs.sh to use dynamic account names for certificate generation.
- Improved add-account.sh to handle missing accounts.env file gracefully.
- Enhanced run-server.sh to support Caddy integration and OAuth options.

.gitignore

@@ -1,2 +1,3 @@
 storage
 test
+Caddyfile