sql, test: automate test failure analysis

## Summary

This issue builds intends to build on PR #163840 so that test failures can be automatically analyzed without the need to automatically kick off the `/investigate` command.

## Details

When a new `C-test-failure` issue is open against the `T-sql-foundations` team, an AI agent should perform some preliminary analysis to determine if the issue is likely to share a common root cause with another open issue. For any new test failure, the `/investigate` command should be run automatically.

We can evaluate expanding this work to other components once we have it successfully running against SQL Foundations test issues.

Epic: CRDB-60540

Jira issue: CRDB-60542