Describe the problem

Currently the \c command in the shell doesn't know how to generate TLS client cert/key paths when switching users or servers. This makes it hard to:

• change from one user to another when both use TLS client cert authn and the cert/key files are known for both
• change from non-root user in app tenant to root user in system tenant in shared-process multitenancy

Expected behavior

We'd like an option for \c to auto-compute cert and key directories.

Epic: CRDB-26691

Jira issue: CRDB-27201