Hello, just have a question. I want to secure my tool API routes by using the x-vapi-secret header for authentication. My goal is to create a unique secret for each user based on their UID and validate this on my server. Here’s my planned approach: 1. Generate a user-specific secret using HMAC (e.g., hash of UID + master key). 2. Set the secret to tool on Vapi for each user. 3. Validate incoming requests by recomputing the expected secret based on the UID and secret in the request headers. Is this approach secure and efficient? Are there better ways to handle user-specific secrets for API route authentication in Vapi?