feat(solana): add gasValue flag to GMP script

[Deiadara]

why

GMP Solana Scripts were missing auto gas payment

how

---

Note

Medium Risk
Adds an optional PayGas instruction and changes CallContract transaction construction to bundle multiple instructions in one transaction, which could affect how transactions are serialized/signed and how gas is attributed/refunded.

Overview
Adds --gas-value and optional --refund-address to the CallContract CLI so GMP calls can atomically pay cross-chain gas in the same Solana transaction.

Updates build_transaction/call_contract to emit a two-instruction bundle (PayGas via solana_axelar_gas_service + gateway CallContract) keyed by a keccak payload_hash, with refund defaulting to the fee payer.

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