the retry warning logged index/last_index (attempts-1), so a 3-attempt retry showed 'retry 1/2'. now logs index+1 of attempts. both retry and aretry.
Signed-off-by: disqualifier <dev@disqualifier.me>
add commons.retry: exponential-backoff retry as sync `retry` and async `aretry`,
each usable as a call form or a decorator. backoff is min(backoff*factor**n,
max_backoff) with optional full jitter; the schedule is a pure generator so it
tests without real sleeps (sleep + rand injectable). `on=` narrows retryable
exception types, `give_up(exc)` stops early on a non-retryable error, and after
attempts are exhausted the LAST exception is re-raised (fail loud, never swallowed).
de-dups retry logic written 3x divergently (aiowebhooks 429/5xx, aioproxies
burn/rotate, aiomail reconnect).
Signed-off-by: disqualifier <dev@disqualifier.me>
