- Consolidated and modularized `eslint.config.mjs` with defined rules for source, test, E2E, and scripts.
- Improved test and E2E rules with relaxed settings for flexibility and enhanced mocking.
- Standardized variable naming and removed redundant imports in unit and E2E tests.
- Updated error handling and comments to align with modern TypeScript best practices (e.g., `@ts-expect-error`).
- Added `merge-coverage.ts` to combine Jest and Playwright coverage into a unified report with comprehensive statistics and thresholds.
- Included `convert-v8-to-istanbul.ts` for transforming Playwright V8 coverage into Istanbul format, enabling seamless merging.
- Introduced E2E coverage helpers for Playwright tests (`startCoverage`, `stopAndSaveCoverage`, `withCoverage`) to collect and process both V8 and Istanbul coverage.
- Configured `.nycrc.json` with coverage thresholds and reporting formats for improved visibility and enforcement.
