WalletBeat simulation: adversarial outcome warnings

[0xpantera]

Problem

WalletBeat transaction-simulation fixtures include adversarial cases: misleading selectors, fake airdrops/balance drains, volatile outcomes, and guaranteed reverts. Deckard currently classifies calldata by known selectors and does not yet run a full state-diff simulation.

Scope

• Simulate execution against verified local state before signing.
• Compare claimed selector semantics with actual asset deltas.
• Warn on balance drains, volatile block-dependent outcomes, and guaranteed reverts.
• Do not rely on selector names alone for user-facing safety claims.

Acceptance criteria

• WalletBeat misleading-selector, fake-airdrop, volatile-outcome, and failing-transaction have positive warning/refusal coverage.
• The ERC-20 selector-on-non-token ambiguity is explicitly covered.