Bug Description

I tried to use the proxy with a cloud sql instance using Postgres 18. It seems like the proxy is detecting it as a MySQL instance trying to connect on 3337, making it unusable.

2025/10/27 07:12:52 proxy server error: dial error: failed to dial (connection name = "#########"): dial tcp ########:3307: connect: connection refused

It should be compatible with the versions offered in cloud sql, especially given that we can't rollback an upgrade in CLoud SQL.

Thank you

Example code (or command)

// paste your code or command here

Stacktrace

Steps to reproduce?

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Environment

1. OS type and version:
2. Cloud SQL Proxy version (./cloud-sql-proxy --version):
3. Proxy invocation command (for example, ./cloud-sql-proxy --port 5432 INSTANCE_CONNECTION_NAME):

Additional Details

No response