ci: add GitHub Actions workflow for frontend E2E testing (#1262)

[GhulamMustufa]

Overview

Configure .github/workflows/frontend-e2e.yml running build, lint, unit tests, and the Playwright E2E matrix on every pull request and push to main, closing #1262.

Closes #1262

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Scope & Changes Made

1. GitHub Actions CI Workflow (.github/workflows/frontend-e2e.yml) [Core Deliverable]

• Triggers: Pull requests affecting react/**, sdk/**, or .github/workflows/frontend-e2e.yml, plus push to main and manual dispatch.
• Environment: Node.js 22 LTS with caching.
• Pipeline: Installs workspace and demo dependencies, builds SDK & React packages, runs linter and unit tests (166 tests passing), installs Playwright Chromium with OS dependencies, and runs npm run e2e.
• Diagnostics: Automatically uploads Playwright HTML report and traces as GitHub Actions artifacts on failure.

2. E2E Test Fixtures & Navigation (react/e2e/)

• react/e2e/stubs.ts:
  • Replaced invalid dummy key with a valid checksummed ed25519 Stellar address (GBX6IWES6LXR37NISD3DKBJSSWEGGY6UB5PSL3UVTJEZRIJ4GUPJAWVE).
  • Replaced invalid simulation XDR 'AAAAAQAAAAA=' with authentic 4-byte xdr.ScVal.scvVoid() base64 'AAAAAQ==' to prevent @stellar/stellar-sdk unhandled buffer overflow during buildUnsignedTransaction.
  • Added sequence 1000 response handler to getLedgerEntries mock.
• Spec Navigation (mint.spec.ts, burn.spec.ts, transfer.spec.ts, roles.spec.ts, vaults.spec.ts):
  • Replaced hard browser reloads (page.goto('/#/screen')) with UI link navigation (page.getByTestId('nav-...').click()) to preserve in-memory wallet connection state across screens during user flows.

3. State & Context Integration (react/src/screens/ & sdk/src/)

As outlined in the Phase 3 scope ("Integrate with existing contexts (BcForgeProvider, WalletProvider) and SDK methods where applicable"):

• react/src/screens/VaultsScreen.tsx: Added fallback to context wallet adapter (useWalletContext().adapter / contextClient.getWalletAdapter()) so VaultsScreen can sign deposit and withdraw transactions when rendered inside <WalletProvider>.
• sdk/src/vaultClient.ts: Enhanced invokeContract to accept a WalletAdapter as the transaction signer without requiring a raw secret Keypair.
• sdk/src/client.ts: Added fallback to response.txHash when reading transaction results from Soroban RPC to ensure compatibility across RPC versions.

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Verification & Test Results

• Playwright E2E Suite: 17/17 tests passing (13.5s) on GitHub Actions CI (Run #39143824995).
  • mint.spec.ts: 3/3 passed
  • burn.spec.ts: 3/3 passed
  • transfer.spec.ts: 3/3 passed
  • roles.spec.ts: 6/6 passed
  • vaults.spec.ts: 2/2 passed
• Unit Tests: 16/16 test suites passed (166 unit tests).
• Visual Snapshots: Passing.
• Mergeability: Clean merge against upstream/main with zero conflicts.