feat: Add Suwappu DeFi tools for cross-chain token operations

[0xSoftBoi]

Summary

Adds a suite of 5 DeFi tools for cross-chain token operations via the Suwappu DEX aggregator API:

• SuwappuGetPricesTool — real-time USD prices and 24h changes for any token
• SuwappuGetQuoteTool — swap quotes with price impact, optimal route, gas estimates, and fees
• SuwappuGetPortfolioTool — wallet token balance tracking across all supported chains
• SuwappuListChainsTool — discover all 15+ supported blockchain networks
• SuwappuListTokensTool — list available tokens on a specific chain

Supports Ethereum, Base, Arbitrum, Solana, and 10+ more networks.

What's included

• Tool implementations following BaseTool pattern with Pydantic schemas, EnvVar declarations, and proper async handling
• Full test suite (12 tests) with mocked API calls — no network access required
• README with usage examples and setup instructions
• Registered in __init__.py and __all__

Dependencies

• suwappu (peer dependency, lazy-imported with helpful error message if missing)

Test plan

• All 5 tools have initialization tests verifying name and description
• All tools with API calls have mocked integration tests verifying correct arguments and response parsing
• Edge case: optional chain parameter correctly passes None when empty
• All async client connections properly closed in finally blocks