withRetry throws undefined when maxAttempts is 0 or negative — no precondition guard

[ooloth]

Why

If maxAttempts is passed as 0 or a negative number, withRetry's loop body never executes and the function falls through to throw lastError! where lastError was never assigned — throwing undefined as a non-null-asserted never-type, producing an unintelligible failure.

Current state

io/utils/retry.ts line 59: for (let attempt = 1; attempt <= opts.maxAttempts; attempt++). When maxAttempts is 0, the loop body never runs. Line 78: throw lastError! — TypeScript's non-null assertion silences the type error, but lastError is undefined at runtime, so the throw propagates undefined rather than a real error.

Ideal state

• withRetry validates opts.maxAttempts >= 1 at entry with a clear error (e.g. invariant(opts.maxAttempts >= 1, 'maxAttempts must be at least 1')).
• Calling withRetry with maxAttempts: 0 produces an immediate, descriptive error rather than a confusing undefined throw.

Starting points

• io/utils/retry.ts — lines 59 and 78, the loop guard and the final throw

QA plan

1. Call withRetry(fn, { maxAttempts: 0 }) — expect an immediate error naming the invalid maxAttempts, not a throw of undefined.
2. Call withRetry(fn, { maxAttempts: 3 }) — expect normal retry behaviour unchanged.

Done when

withRetry throws a descriptive error at entry when maxAttempts is less than 1, rather than eventually throwing undefined.