Add circuit_breaker package

[manelsen]

Summary

• Adds circuit_breaker (category: Erlang and OTP) — circuit breaker for Gleam with closed, open, half-open state machine and OTP actor support

Package

• Hex: https://hex.pm/packages/circuit_breaker
• Docs: https://hexdocs.pm/circuit_breaker/
• Repo: https://github.com/manelsen/circuitbreaker
• License: Apache-2.0

The package provides a pure state machine for circuit breaker logic, an OTP actor for thread-safe multi-key management, and a global registry via persistent_term. Published on Hex, v2.0.0.

[lpil]

Thank you, but there's some issues that makes me reluctant to add this to the awesome list:

• The private internals of the gleam_erlang library is being violated in the Erlang FFI.
• The persistent term storage system is being misused to create a name-like system.
• The start function doesn't return [actor.Started](https://hexdocs.pm/gleam_otp/1.2.0/gleam/otp/actor.html#Started)
• The supervised function is absent.
• The API is split across 3 modules and 2 of them have very generic names. "actor" especially is going to clash for users.
• The API and documentation are a bit confusing, so it is not clear to be how the library is intended to be used.
• The names such as cb and check_and_call were confusing to me, as they don't seem to match what the code does.

This list is used as a reference for folks and to find production-suitable dependencies, so we want the code added to be as good as possible!