Add E2E and integration tests

Add comprehensive test coverage for:
- Google OAuth flow (login, logout, session persistence, error handling)
- Wallet connections (Keychain, PeakVault, MetaMask, Google Drive, HTM)
- Account management (display, creation, switching)
- Token operations (list, create, transfer, search)
- Transaction signing and memo encryption
- API response integration tests
- Store integration tests (settings, tokens, wallet)

Test infrastructure:
- Playwright configuration for headless and headed testing
- Mock wallets (Keychain, PeakVault, MetaMask, HTM)
- API mocks for Hive, Google, and CTokens APIs
- Page objects for consistent test interactions
- Helper utilities for auth setup and state management
- Test fixtures with accounts, tokens, and mock responses

🤖 Generated with [Claude Code](https://claude.com/claude-code

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