ci: add pull request quality gate

[andrei-hasna]

Summary

• run frozen dependency installation, build, typecheck, and the full test suite on pull requests and pushes to main
• add a dedicated typecheck package script
• isolate the local collector command stub so it cannot replace the real timeout implementation in another test file

Testing

• bun install --frozen-lockfile
• bun run build
• bun run typecheck
• bun test (278 passing across 26 files; no exclusions)