parameters for chain exercises

[n13]

Summary

Adds two parameters to quantus exercise so the suite can run against any funded account — e.g. a public testnet — instead of requiring the genesis-funded crystal_alice dev account and ~4000 tokens.

What's new

• --root-account <NAME> (+ --root-password / --root-password-file) — the wallet that funds the run. Defaults to the built-in crystal_alice dev account, so existing --dev usage is unchanged. Threaded through the funding step and the wormhole scenario.
• --total-amount <TOKENS> (default 40) — total budget drawn from the root account, split evenly across the ephemeral test accounts.

How it works

• Discretionary test amounts (transfers, multisig funding, reversible, fuzz, …) are scaled down by a fixed DISCRETIONARY_SCALE = 100 via a new ctx.test_unit = unit / 100, so the suite needs ~tens of tokens instead of ~4000.
• Fixed, chain-imposed amounts are never scaled — existential deposit and the multisig / preimage / governance deposits are read from the chain, so they stay covered. That's why the practical floor is ~40 tokens, not ~1.
• Preflight + guards replace the old cryptic mid-run failure (Inability to pay some fees) with fast, actionable errors:
  • root-account balance check before any funding,
  • "budget too low to cover deposits" guard,
  • existential-deposit floor guard on the scale (a fresh account funded with test_unit/2 must stay above ED).
• The wormhole amount is intentionally left unscaled (50.0): it round-trips back to the wallet and draws from the separately-funded root account, so shrinking it saves nothing — and small per-proof amounts round below the on-chain minimum in later rounds (No transfer event found).

Caveat

The governance phase still relies on the dev genesis accounts (tech-collective membership), so pass --skip governance when using a custom root account on a public testnet. This is documented in --help.

Testing

• Local --dev node (spec 135 / tx 3): full suite 62/62 passing with --root-account crystal_alice --total-amount 40 — funds 4 ephemeral accounts at 10 DEV each; multisig, governance, preimage (all deposit-bearing) and wormhole all green.
• Live Planck testnet: preflight balance check, budget-too-low guard, and custom-root wallet loading all verified.

quantus exercise --skip governance \
  --root-account <wallet> --root-password <pw> \
  --total-amount 40 --node-url <ws-url>

Docs

quantus exercise was previously undocumented — added a Chain Exercise Suite section to the README (phases, dev-node vs. testnet usage, and a flag table). All new flags are also self-documented in --help.