fix: F-2026-18800 | [Dual Defense] Short SVM send_funds Defaults TxType=0 While Claiming Funds → Mapped to GAS

[Aman035]

decodeUniversalTxEvent accepted a truncated event, logged "defaulting to Funds", then set TxType = 0. Wire 0 is GAS, not FUNDS.

GAS credits the sender UEA via swap; FUNDS deposits PRC20 to the recipient. Same amount, different party. TxType 0 also selects FAST confirmation, so a truncated FUNDS transfer lost finality too.

• SVM: every field through signature_data now required, truncation is an error. from_cea stays optional.
• EVM: same hole, a log under five static words was stored with TxType left at 0. Now rejected.
• Malformed events are discarded, not stored with empty event data.
• Not reachable today: the gateway always emits the full 142-byte layout and forged logs were already blocked. This closes the path.

Tests: three real devnet events as fixtures, every truncation of them rejected, leniency tests inverted, constructInbound pinned so FUNDS never becomes GAS. 8 mutations, all caught.

Also here: event cleaner race. TestEventCleanerStop already failed under -race on audit-fixes. The goroutine now owns its ticker and stop channel, running/stopCh are behind a mutex, and Stop waits so shutdown cannot close the chain DB under an in-flight cleanup. 5 mutations, all caught.