feat(bdd): add Python BDD tests and reorganize test structure

[hubcio]

Introduces cross-SDK BDD testing framework with Python implementation
alongside existing Rust tests. Moves BDD tests from core/bdd to a
dedicated top-level bdd/ directory organized by language.

• Add Python BDD tests using pytest-bdd for basic messaging scenarios
• Reorganize Rust BDD tests from core/bdd/ to bdd/rust/
• Create Docker infrastructure for running multi-SDK tests
• Add run-bdd-tests.sh script for easy test execution
• Share Gherkin feature files across all SDK implementations

[chengxilo]

Is it possible to organize the Dockerfiles by placing each one in its respective language folder and naming them simply Dockerfile? For example:

.
└── bdd/
    ├── python/
    │   ├── Dockerfile (move Dockerfile.python here)
    │   ├── tests/
    │   │   └── ...
    │   └── requirements.txt
    ├── rust/
    │   ├── Dockerfile (move Dockerfile.rust here)
    │   ├── tests/
    │   │   └── ...
    │   └── Cargo.toml
    ├── Dockerfile (rename Dockerfile.server to Dockerfile)
    ├── README.md
    ├── basic_message.feature
    └── docker-compose.yml

I believe this structure will be better for future development. Also, some IDEs may not recognize files like Dockerfile.python or Dockerfile.rust as Dockerfiles, so renaming them to just Dockerfile inside each language folder improves IDE support and clarity.

[hubcio]

Is it possible to organize the Dockerfiles by placing each one in its respective language folder and naming them simply Dockerfile? For example:

.
└── bdd/
    ├── python/
    │   ├── Dockerfile (move Dockerfile.python here)
    │   ├── tests/
    │   │   └── ...
    │   └── requirements.txt
    ├── rust/
    │   ├── Dockerfile (move Dockerfile.rust here)
    │   ├── tests/
    │   │   └── ...
    │   └── Cargo.toml
    ├── Dockerfile (rename Dockerfile.server to Dockerfile)
    ├── README.md
    ├── basic_message.feature
    └── docker-compose.yml

I believe this structure will be better for future development. Also, some IDEs may not recognize files like Dockerfile.python or Dockerfile.rust as Dockerfiles, so renaming them to just Dockerfile inside each language folder improves IDE support and clarity.

sure, will change this

[hubcio]

@chengxilo you can check now, I adjusted the bdd directory structure according to your comment.

[chengxilo]

@chengxilo you can check now, I adjusted the bdd directory structure according to your comment.

It looks amazing! Thank you for taking my suggestion. Please merge it asap, lol😂