Add contract deployment helper functions

Add SDK functions to deploy and initialize the SoroSave contract.

**Acceptance Criteria:**
- Add `deployContract(wasmPath, admin)` function
- Add `initializeContract(contractId, admin)` function
- Handle WASM upload and contract instantiation
- Return deployed contract ID
- Add deployment verification step

**Files:** new file `src/deploy.ts`, `src/index.ts`