Function create_mock_tempo_sig 

fn create_mock_tempo_sig(
    key_type: &SignatureType,
    key_data: Option<&Bytes>,
    key_id: Option<Address>,
    caller_addr: Address,
    is_t1c: bool,
) -> TempoSignature

Available on crate feature tempo-compat only.

Creates a mock AA signature for gas estimation based on key type hints

• key_type: The primitive signature type (secp256k1, P256, WebAuthn)
• key_data: Type-specific data (e.g., WebAuthn size)
• key_id: If Some, wraps the signature in a Keychain wrapper (+3,000 gas for key validation)
• caller_addr: The transaction caller address (used as root key address for Keychain)
• is_t1c: Whether T1C is active — determines keychain signature version (V1 pre-T1C, V2 post-T1C)