Implement @lytics/playwright-adapters (Filesystem & Slack)

[prosdev]

Branch: feat/implement-public-adapters

Priority: Medium

Estimate: 2-3 hours

Parent Epic: #1

Dependencies: #2

Description

Create generic, reusable adapters for filesystem storage and Slack notifications. These adapters are product-agnostic and useful for any team adopting the reporter framework. FilesystemAdapter provides local JSON storage for development/debugging. SlackAdapter sends formatted test summaries to Slack channels.

Acceptance Criteria

• FilesystemAdapter writes JSON files to specified directory with configurable formatting
• SlackAdapter sends formatted messages to Slack webhook with test stats, failures, and flaky tests
• Both adapters implement ResultAdapter interface
• Unit tests pass with 80%+ coverage
• Can be used standalone or combined with other adapters
• Published to public npm registry
• README includes configuration examples and screenshots

Technical Requirements

• Implement FilesystemAdapter with directory creation and JSON writing
• Migrate Slack notification logic from slack-reporter.ts to SlackAdapter
• Add configurable message formatting for Slack (success/failure colors, emoji, etc.)
• Add TypeScript examples for both adapters
• Support environment variable configuration (SLACK_WEBHOOK_URL, etc.)
• Handle file system errors gracefully in FilesystemAdapter

New Files

• packages/adapters/src/filesystem/FilesystemAdapter.ts
• packages/adapters/src/filesystem/FilesystemAdapter.test.ts
• packages/adapters/src/slack/SlackAdapter.ts
• packages/adapters/src/slack/SlackAdapter.test.ts
• packages/adapters/README.md