feat(wasm-solana): add transaction building support

Add comprehensive transaction building capabilities to wasm-solana,
enabling construction of various Solana transaction types via WASM.

## Core Infrastructure
- TransactionIntent type for specifying transaction parameters
- Support for blockhash and durable nonce sources
- Automatic nonce advance prepending for durable nonce transactions

## Supported Instructions
- System Program: Transfer, CreateAccount, NonceAdvance, NonceInitialize,
  Allocate, Assign
- Stake Program: Initialize, Delegate, Deactivate, Withdraw, Authorize
- SPL Token: Transfer (via TransferChecked), CreateATA, CloseATA
- SPL Stake Pool (Jito): DepositSol, WithdrawStake
- Compute Budget: SetComputeUnitLimit, SetComputeUnitPrice
- Memo Program

## TypeScript API
- buildTransaction(intent: TransactionIntent): Uint8Array
- Full TypeScript types for all instruction variants
- Builder types prefixed to avoid conflicts with parser types

Ticket: BTC-2955

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

Author: lcovar