Add Solana swap endpoints and refactor chainId handling

Introduces new endpoints for fetching swap quotes and executing token swaps on Solana, including request/response models. Refactors Solana-related methods and models to use string-based chainId (CAIP-2 or legacy EVM IDs) instead of custom ChainId classes. Updates response and request types for Solana transaction and chat endpoints, adds new enum values, and improves documentation for blockchain network identifiers.

Author: 0xFirekeeper