dev: run the supply property/fuzz spec on the live harness

Parent: #665
Depends on the core harness (#666).

Scope

The token supply property/fuzz spec (NativeShieldedTokenSupply.property.test.ts) is currently dry-only (describe.skipIf(isLiveBackend())), left out of the live run on a feasibility ground, not a coverage one:

• fast-check drives 15 randomized runs of up to 6–8 mint/burn ops each, and every op is its own deploy/tx on the live backend (~18s apiece), so the file would run for hours; and
• the random op sequences are non-deterministic, so the two-round flake classifier in scripts/test-live.ts (re-run a failed file to tell a real failure from an environment flake) cannot reproduce a failing case.

The deterministic scalar/family supply specs already exercise the same NativeShieldedTokenSupplyCore accounting live, so the invariant is covered on the node. This issue tracks the optional extra of fuzzing it live.

• Pin a fixed fast-check seed so runs are reproducible (the flake classifier needs determinism).
• Reduce numRuns on live (env-gated) to keep the job within its budget.
• Un-gate the spec and confirm green on make env-up.

Introduced alongside the token/access/security/crypto/utils live rollout.