feat: alert knob using pydantic

[sinapah]

Issue

Implements the config validation logic from #205 using Pydantic.

Solution

Checklist

• I have added or updated relevant documentation.
• PR title makes an appropriate release note and follows conventional commits syntax.
• Merge target is the correct branch, and relevant tandem backport PRs opened.
• This change warrants a release, so I have updated the project.version field in the pyproject.toml file.

Context

Testing Instructions

Upgrade Notes