Python SDK: Add TCP/TLS support, integration tests and examples

[mmodzelewski]

Summary

The Python SDK (PyO3-based wrapper around the Rust SDK) currently only exposes a plain TCP connection via `IggyClientBuilder::new().with_tcp()`. There is no way to enable TLS from the Python API, and there are no TLS integration tests or examples.

Current State

• TLS implementation: Not exposed to Python users. The `IggyClient.init` method in `foreign/python/src/client.rs` hardcodes `IggyClientBuilder::new().with_tcp().with_server_address(...).build()` with no TLS options. The `from_connection_string` classmethod could potentially support TLS via connection string, but this is not documented or tested.
• Integration tests: No TLS tests exist
• Examples: No TLS-specific examples in `examples/python/`

Requirements

TLS Support

• Expose TLS configuration options in the Python `IggyClient`:
  • Option to enable TLS on TCP connections
  • Option to specify CA certificate file path
  • Option to specify TLS domain
  • Either via constructor parameters or via a builder pattern
• Ensure `from_connection_string` works with TLS connection strings and document this

Integration Tests

• Add integration test(s) that connect to a TLS-enabled Iggy server from Python
• Use custom certificates from `core/certs/` (`iggy_ca_cert.pem`, `iggy_cert.pem`, `iggy_key.pem`)
• Test scenarios:
  • Successful TLS connection with custom CA certificate
  • Basic message send/receive over TLS connection

Examples

• Add a TLS example in `examples/python/` demonstrating:
  • How to configure the client with TLS enabled
  • How to specify a custom CA certificate file
  • A simple producer/consumer flow over TLS

Reference

• Python client implementation: `foreign/python/src/client.rs`
• Server TLS config env vars: `IGGY_TCP_TLS_ENABLED=true`, `IGGY_TCP_TLS_CERT_FILE`, `IGGY_TCP_TLS_KEY_FILE`
• Custom certs location: `core/certs/`
• Rust SDK TLS support (underlying): `core/sdk/src/tcp/tcp_tls_connection_stream.rs`