feat: implement WebAssembly Merkle Tree Module for client-side proof …

[dev-king-001]

Description

Implement a WebAssembly (WASM) based Merkle Tree module to significantly improve client-side performance for tree construction and proof generation. This introduces a Rust-compiled WASM implementation along with a Web Worker wrapper to offload heavy cryptographic operations from the main thread.

Closes #62

Changes Made

• Rust WASM Module: Added a high-performance Rust implementation of a Merkle Tree in rust/merkle/ compiled to WebAssembly.
• WASM Loader: Created src/utils/wasmLoader.ts to reliably fetch and instantiate the compiled .wasm binary.
• TypeScript Wrapper: Created src/utils/merkleWasm.ts to handle memory allocation and provide a clean TypeScript interface to the WASM exports (buildTree, generateProof, verifyProof).
• JS Fallback Integration: Added src/utils/merkleTree.ts to route calls through the WASM module if available, or fall back to a JavaScript stub if initialization fails.
• Web Worker Support: Introduced src/workers/merkleWorker.worker.ts to execute Merkle tree tasks entirely off the main UI thread, using transferable ArrayBuffers for zero-copy performance.
• Benchmarks: Added performance benchmark tests (src/tests/merkleWasm.bench.ts) to track and enforce minimum hash rates and proof generation times.
• Config Updates: Updated vitest.config.ts to include .bench.ts files in the test suite.

Verification

• Ensure benchmark tests pass and performance metrics are met.
• Verify that WASM module loads successfully in the browser.
• Confirm Web Worker offloads tasks without blocking the main UI thread.

[elizabetheonoja-art]

LGTM