refactor: optimize cache-config.ts structure

[cypherpepe]

This pull request refactors the cache-config.ts file to improve its structure for better readability and maintainability. The key changes include:

• Consolidation of repeated logic for subgraph URL generation.
• Separation of chain-specific configurations for v2, v3, and v4 to ensure correctness and flexibility.
• Clear parameter configuration for timeouts, thresholds, and other protocol-specific settings.
• Enhanced scalability for adding or modifying chain mappings in the future.

This refactor introduces no new functionality but ensures the existing logic is cleaner, more modular, and easier to extend.