feat(review): path-scoped review instructions

[devops-thiago]

Problem Statement

Repository instructions are global (.github/thrillhousebot.md). Path-scoped instructions would let different directories carry different review rules (e.g. stricter rules for payments/, relaxed for generated code).

Proposed Solution

Support path-scoped instruction blocks — either glob-keyed sections within the instructions file or per-directory instruction files — and apply the matching rules to findings in files under those paths. Reuse the existing glob matching in ReviewDiffFormatter.

Alternatives Considered

• Keep global-only instructions — simpler but less expressive for monorepos.

Priority

Important

Code of Conduct

• I have searched for existing issues and this is not a duplicate.