Standardizes retry/backoff behavior for cf-core modules and products that
make external calls, replacing ad-hoc per-product retry loops. Wraps
backon (MIT, zero stdlib deps) — chosen over tenacity/backoff per the
eval in #65 for native async support, circuit breaker/hedging primitives,
and a process-wide enable/disable toggle ideal for tests.
Ships the standalone wrapper only; wiring it into llm/affiliates/reranker/
activitypub is left as follow-up work per module rather than retrofitting
LLMRouter's existing fallback-chain error handling in the same change.
Bump to 0.22.0.
Closes: #65
