ArbitraryInstances

Token quantities, bounded to what a Value may legally hold.

Same edge-case shape as iArb, but its wide [-2^128, 2^128] branch is narrowed to [-2^64, 2^64]: real ledger quantities fit Int64, and the CIP-153 builtins that Value operations lower to at PV11 reject quantities beyond +-(2^127) and fail when a unionValue/scaleValue result leaves that range (see docs/superpowers/specs/2026-08-18-t7-value-builtins-lowering-design.md). The bound stays well below 2^127 so that summing the up-to-11 generated assets cannot overflow either.

The * properties test in ValueTest couples its +-(2^62) scaling-factor bound to this +-(2^64) amount bound (2^64 * 2^62 = 2^126), so widening this bound means narrowing that one in step.

Generates a random asset name, which is a ByteString of length between 1 and 32 bytes.