feature: add usn and wankr

[xr9kayu]

This pull request adds support for two new collateral tokens, WANKR and USN, across the codebase. It updates environment variables, type definitions, constants, and token lists to ensure these new tokens are recognized and handled properly in both the frontend and UI kit. Additionally, some configuration values and legacy flags have been updated for consistency.

New Collateral Token Support

• Added WANKR and USN to the list of supported pools in generateStaticParams functions for both layout.tsx and page.tsx, enabling routing and pages for these tokens. (frontend/app/src/app/earn/[pool]/layout.tsxR10-R11, frontend/app/src/app/earn/[pool]/page.tsxR7-R8)
• Updated type definitions and utility functions in tokens.ts to include WANKR and USN as valid TokenSymbol and CollateralSymbol values, and added their configuration to the COLLATERALS and TOKENS_BY_SYMBOL lists. [1] [2] [3] [4] [5]
• Extended the collateral symbol schema in env.ts and updated related validation logic to recognize WANKR and USN.
• Increased the MAX_COLLATERAL_DEPOSITS constant to support high deposit limits for WANKR and USN.

Environment and Configuration Updates

• Added new environment variables and contract addresses for WANKR and USN in .env, including placeholders for leverage zapper and other contract helpers. [1] [2] [3] [4] [5]
• Changed the LEGACY_CHECK default value from "true" to "false" in both .env and validation schema, and updated chain explorer format for NeuraTestnet. [1] [2]

These changes ensure the application can handle the new collateral types seamlessly and maintain consistency in configuration and validation.