fix(core): PHPMNT-394 Normalise maxSize so invalid values cannot disable memoization

[TomA-R]

Jira: PHPMNT-394

What/Why?

A fractional or negative maxSize silently turns memoization off entirely:

const memoized = memoize(fn, { maxSize: 0.5 });
memoized(1, 1); // fn runs
memoized(1, 1); // fn runs again — every call is a miss

With maxSize: 0.5, the LRU set (size 1 after the first call) always "exceeds" the limit, so the key that was just issued is immediately expired — every call recomputes and the consumer gets no signal that anything is wrong. Negative and NaN values behave the same way, and Infinity has the opposite problem: every key is tracked for expiry but none ever expires, so the tracking set grows forever. The maxSize type is number, so a computed value can hit any of these without a type error.

Fix: the resolver now floors fractions and treats anything below 1 or non-finite as "no limit" (Number.isFinite(maxSize) ? Math.max(0, Math.floor(maxSize)) : 0). So 2.7 behaves as 2, while 0.5, -1, NaN, and Infinity behave as the default unlimited cache — degraded gracefully instead of silently misbehaving.

Rollout/Rollback

Merge / revert

Testing

Tests added at the resolver level (below-one values, non-finite values, fractional flooring) and the memoize level.