Interface ExitFeeWallet

Fee source for graph-mode bump steps. Given a parent tx carrying a P2A anchor, it builds and signs the CPFP fee child from its own funds and returns the 1P1C package hexes (parent unchanged, child signed) — WITHOUT broadcasting; the executor owns broadcast. OnchainWallet implements it.

interface ExitFeeWallet {
    bumpAnchor(
        parentHex: string,
        feeRate: number,
    ): Promise<[parentHex: string, childHex: string]>;
}