feat: add wrapSol/unwrapSol helpers for wSOL operations

[GuiBibeau]

Summary

• Add WsolHelper with sendWrap() and sendUnwrap() methods for wrapping/unwrapping SOL
• Add useWrapSol() React hook with balance tracking and status management
• Export WRAPPED_SOL_MINT constant and all related types
• Add WrapSolPanel example component to vite-react demo

Usage

// Client helper
const wsol = client.wsol;
await wsol.sendWrap({ amount: 1_000_000_000n, authority: session });
await wsol.sendUnwrap({ authority: session });

// React hook
const { wrap, unwrap, balance, isWrapping, isUnwrapping } = useWrapSol();
await wrap({ amount: 1_000_000_000n });
await unwrap({});

Test plan

• Build passes
• Typecheck passes
• Tested wrap/unwrap in vite-react example app

Closes #116