feat(e2e): add Playwright end-to-end testing setup with PostgreSQL and wallet integration
- Introduced Dockerfile for Playwright to set up the testing environment. - Created docker-compose configuration for orchestrating services including PostgreSQL and the application. - Added detailed instructions for running Playwright tests locally in RUNNING_LOCALLY.md. - Implemented authentication fixtures to handle wallet session management during tests. - Developed wallet fixture for CIP-0030 wallet injection and interaction with the application. - Added global setup for environment variable validation and context loading. - Implemented helper functions for signing transactions and fetching UTxOs from Blockfrost. - Created a comprehensive ring transfer test suite to validate multi-signature transactions. - Added configuration for Playwright tests including output directories and reporting.