Go PR Code Review

## Overview This crystal provides a Go-specialist code review that goes beyond generic style checks. It zeroes in on the failure modes that are unique to Go: goroutine leaks, channel misuse, unsafe concurrent state access, and allocation-heavy patterns — the bugs that slip through standard linters and only surface in production. ## Review Dimensions 1. **Concurrency Safety** — race conditions, improper mutex usage, channel close semantics 2. **Error Handling** — error wrapping with `%w`, sentinel error patterns, panic recovery placement 3. **Performance** — heap escape analysis, slice pre-allocation, `sync.Pool` opportunities 4. **Style** — Effective Go conventions, package and identifier naming, comment formatting