Honor GitHub ruleset required reviewers

When a GitHub repository ruleset requires reviews from specific teams or users, Mergify now waits for those approvals before merging. The new github-require-review-from-specific-teams condition is auto-injected when the engine detects the requirement, and you can reference it explicitly in your .mergify.yml. File-scoped requirements (the ruleset’s file_patterns field) are honored, so a per-directory team approval only kicks in for PRs that touch matching files.