Retrieves the limits for swap route. Token parameters accept either asset names (e.g. USDC, ETH) or token contract addresses (e.g. 0xa0b8…). For native tokens via contract address, use the network’s zero address (e.g. 0x0000000000000000000000000000000000000000 for EVM, 11111111111111111111111111111111 for Solana).