chore: remove outdated documentation files and add compile command tests (#436)

# Removed Auto-Compilation Documentation and Improved Compile Command Testing

This PR removes two documentation files that are no longer needed:
- `COMPILE_WORKER.md` - Documentation about auto-compilation workflow
- `PRD_control-plane-http.md` - Product requirements document for HTTP compilation

Additionally, it enhances the test coverage for the CLI's compile command with several new tests:

- Added tests for migration file generation with proper timestamp formatting
- Added tests for handling empty SQL array responses
- Added tests for creating migrations directory when missing
- Added tests for warning about existing migrations
- Added error handling tests for non-existent Supabase paths
- Added E2E tests for error handling with unknown flows

The PR also improves the ControlPlane tests by adding:
- Tests for flows with dependencies
- Tests for flows with maxAttempts configuration
- Tests for handling compilation errors with proper 500 responses

These changes strengthen the test coverage for the compile command and ensure proper error handling throughout the compilation process.

Author: jumski