chore: add JWT expiry configuration to .env.example

- Added optional JWT_EXPIRY_HOURS setting.
- Defaults to 1 hour if not specified.

Author: fulleni

.env.example

@@ -11,6 +11,10 @@
 # Generate a secure key using: dart pub global run dcli_scripts create_key
 # JWT_SECRET_KEY="your-super-secret-and-long-jwt-key"
 
+# OPTIONAL: The duration for which a JWT is valid, in hours.
+# Defaults to 1 hour if not specified.
+# JWT_EXPIRY_HOURS="1"
+
 # REQUIRED FOR PRODUCTION: The specific origin URL of your web client.
 # This allows the client (e.g., the HT Dashboard) to make requests to the API.
 # For local development, this can be left unset as 'localhost' is allowed by default.