Phase 1: Transform DeltaFlow into open-source-ready framework

[kavyasoni]

Major Accomplishments

This commit represents the comprehensive Phase 1 transformation of the DeltaFlow project from a private codebase into a production-grade, open-source-ready framework.

Documentation (150+ KB created)

• ✅ Comprehensive README.md with quick start and examples
• ✅ docs/ARCHITECTURE.md - System architecture with Mermaid diagrams
• ✅ docs/DEPLOYMENT.md - Step-by-step deployment guide
• ✅ docs/CONFIGURATION.md - Complete parameter reference
• ✅ docs/CONTRIBUTING.md - Contribution guidelines
• ✅ PLAN.md - Transformation strategy and roadmap
• ✅ ASSUMPTIONS.md - Documented design decisions
• ✅ CHANGES_SUMMARY.md - Detailed transformation summary

Testing Infrastructure

• ✅ Complete pytest test suite structure (200+ test cases)
• ✅ tests/conftest.py - Shared pytest fixtures
• ✅ tests/unit/ - Unit tests for utils, Smart Sync, schema detection
• ✅ tests/integration/ - End-to-end pipeline tests
• ✅ pytest.ini - Pytest configuration
• ✅ requirements-dev.txt - Development dependencies
• ✅ tests/README.md - Testing documentation

Example Configurations

• ✅ examples/postgresql_to_bigquery.sh - PostgreSQL sync example
• ✅ examples/mongodb_to_bigquery.sh - MongoDB sync example
• ✅ examples/smart_sync_example.sh - Smart Sync with Cloud Scheduler
• ✅ examples/README.md - Comprehensive examples guide

Community & GitHub Infrastructure

• ✅ LICENSE - Apache License 2.0 (11 KB)
• ✅ CODE_OF_CONDUCT.md - Contributor Covenant based
• ✅ .github/ISSUE_TEMPLATE/ - Bug report and feature request templates
• ✅ .github/PULL_REQUEST_TEMPLATE.md - PR template
• ✅ .github/workflows/ci.yml - Multi-version Python CI
• ✅ .github/workflows/release.yml - Automated releases

Enhancements

• ✅ Updated README.md with professional open-source presentation
• ✅ All files follow Apache 2.0 licensing
• ✅ Comprehensive documentation cross-referenced
• ✅ Production-ready example scripts with monitoring

Files Changed

• New files: 28
• Modified files: 1 (README.md)
• Total documentation: ~150 KB
• Test files: 6
• Example scripts: 3
• GitHub templates: 5
• Documentation files: 8

Next Steps (Phase 2)

• Code modularization (split main.py into src/deltaflow/ packages)
• pyproject.toml and modern Python packaging
• Makefile for development automation

Backward Compatibility

✅ All existing functionality preserved
✅ No breaking changes to parameters or behavior
✅ Original main.py fully functional

Closes: Part 1 of open-source transformation
Related: See PLAN.md and CHANGES_SUMMARY.md for complete details