Test/add integration tests

[Jeck0v]

Enhanced test structure:

• 67 integration tests organized by functionality (CLI, Docker generation, boilerplate, structural)
• Lightweight structural tests focusing on logic over format (no heavy snapshot tests)
• Modular boilerplate tests by framework (FastAPI, Go, Flask)

Addition of documentation and modification of the readme file

  docs/
  ├── INSTALLATION.md     # Complete installation guide (Makefile, Windows, manual)
  ├── DSL_REFERENCE.md    # Complete DSL syntax and directives reference
  ├── EXAMPLES.md         # Practical .ath file examples
  ├── BOILERPLATE.md      # Project generator documentation
  ├── ARCHITECTURE.md     # System design and components
  ├── DEVELOPMENT.md      # Contributing and development workflow
  └── TESTING.md          # Comprehensive test suite documentation