Set up Spark Bitcoin L2 wallet capabilities for AI agents. Initialize wallets from mnemonic, transfer sats and tokens, create/pay Lightning invoices, manage deposits and withdrawals. Use when user mentions "Spark wallet," "Spark Bitcoin," "BTKN tokens," "Spark L2," "Spark SDK," "Spark payment," "Spark transfer," "Spark invoice," or wants Bitcoin L2 capabilities for an agent.