feat: add circuit breaker package for fault tolerance - #3982

use of `time.Sleep` forbidden because "do not sleep in tests: synchronize on channels/require.Eventually, or use fake time in a synctest bubble (nolint with a reason)" (forbidigo)

use of `context.Background` forbidden because "do not use context.Background() in tests, use t.Context()" (forbidigo)

use of `context.Background` forbidden because "do not use context.Background() in tests, use t.Context()" (forbidigo)

use of `context.Background` forbidden because "do not use context.Background() in tests, use t.Context()" (forbidigo)

Error return value of `geminCB.Execute` is not checked (errcheck)

Error return value of `anthropicCB.Execute` is not checked (errcheck)

Error return value of `openaiCB.Execute` is not checked (errcheck)

Error return value of `cb.Execute` is not checked (errcheck)

Error return value of `cb.Execute` is not checked (errcheck)