Spec wording tightened for iterators, integers, and Temporal

Iterator and numeric wording clarified

Iterator builtins now use Number counters — Iterator helpers and array/iterator builtin algorithms now track counters as Number values with explicit 2^53 limits, tightening large-count semantics. Add SnapToInteger for finite-only integer conversion — A new abstract op makes finite-integer conversion and radix bounds checks explicit, and is now used by Number#toString and BigInt#toString.

Temporal terminology updated

Introduce “epoch nanoseconds count” — Temporal-related algorithms now name and constrain epoch timestamps more explicitly, replacing repeated BigInt wording in the spec model.

Other misc changes

• Editorial cleanup in Canonicalize, plus alias/rename follow-ups.
• Regex annex wording and production cleanups, including optional trailing-comma simplifications and Annex B lint prep.
• Function [[Call]]/[[Construct]] editorial alignment, a small clampedLength rename, and IANA time zone link polishing.
• Minor phrasing and algorithm wording tweaks throughout the spec.