Fix/update fix nu6

[sqhell]

Changes

• Migrated from ChainSafe librustzcash fork (46e8ee09) to official zcash/librustzcash (a40ee353) per PR Point upstream librustcash #139
• Updated WebWallet constructor to use new ConfirmationsPolicy API (trusted/untrusted confirmations)
• Added validation module with unit tests for confirmations policy parameter validation
• Fixed e2e test infrastructure: added COOP/COEP headers for SharedArrayBuffer support
• Updated Playwright config with proper browser args and timeout for WASM loading

Details

The breaking change was the Zcash NU6 (Network Upgrade 6) update in the official librustzcash.

Specifically:

Version	Status
ChainSafe fork 46e8ee09	Was working (old)
Official c3425f9c3	Broken (bip32 0.6.0-pre.1 dependency hell)
Official a40ee353	Working (what PR #139 uses)

Quick Checklist for Infra Team

Item	Action Required
COOP/COEP headers	Yes - add to production web server
WebWallet constructor	Yes - update all call sites
Dependencies	No - handled at build time
Database schema	No changes
API endpoints	No changes
Build commands	No changes

Test Before Deploying

They can verify headers are working by checking browser console:
// Should return true if headers are set correctly
console.log(typeof SharedArrayBuffer !== 'undefined')

Tests

Run unit tests for ConfirmationsPolicy validation

cargo test --package webzjs-wallet --lib validation

Run e2e tests (requires yarn and playwright)

cd packages/e2e-tests
yarn install
npx playwright test --project=chromium

Issues

• Fixes compatibility with NU6 network upgrade
• Resolves SharedArrayBuffer initialization failures in Chromium browsers

[irubido]

Looks good to me,
but still wallet does not work when built in WASM.

got this error in browser console

webzjs_wallet.js:1621 panicked at /home/ivan/.cargo/git/checkouts/librustzcash-c2c6180a1a11d4fa/a40ee35/zcash_client_memory/src/wallet_read.rs:734:9:
not yet implemented