Add ai-agent-detect to Agent infrastructure

[Mihailoff]

What

Adds ai-agent-detect to Agent infrastructure, placed by star count.

Inclusion criteria

• CLI/terminal interface: yes — npx ai-agent-detect (human verdict + exit codes, --check <agent>, --format json, --snapshot for contributing probe data).
• What it does / who it's for: a zero-dependency library + CLI that lets CLI tools, loggers, and apps detect which AI coding agent is executing them (normalized name/version/mode from env signals), so they can adapt output. Covers 25 agents with an evidence-tiered registry (probed > source > docs > community) and recorded fixtures — per-agent evidence docs ship in the package.
• Active project: yes — on npm at 0.3.0, tests green (87), MIT.

Happy to adjust wording or placement.