Refactor environment setup and improve pytest coverage

[francescobianco]

This pull request includes several improvements and refactorings across documentation, environment variable handling, middleware, memory store logic, and testing infrastructure. The most significant changes are the removal of legacy K_SERVICE environment variable support in favor of explicit variables, refactoring of memory store logic for clarity and robustness, and the addition of a proper pytest configuration and new tests for the storage backend.

Environment Variable Handling and Documentation:

• Removed all legacy support and documentation for the K_SERVICE environment variable, standardizing on explicit variables like MCP_OPENAPI_ENV, MCP_CACHE_HOST, etc. This affects documentation, server logic, and test scripts, making deployments more portable and the configuration clearer. [1] [2] [3] [4] [5] [6] [7] [8] [9] [10]

Memory Store Refactoring:

• Refactored memory_store.py for improved readability, error handling, and documentation. Exceptions are now more specific, Memcached integration is clearer, and docstrings have been added for key functions. [1] [2] [3] [4]

Middleware and Logging Improvements:

• Improved formatting and readability in logging and middleware, including better line breaks and more descriptive docstrings. Added pylint disables for clarity. [1] [2] [3] [4] [5] [6] [7] [8] [9]

Testing Infrastructure:

• Added a pytest configuration in pyproject.toml and a conftest.py to ensure the src directory is on the Python path for tests. [1] [2]
• Added a new test module test_storage_backend.py with unit tests for local and cloud storage backends, improving coverage and reliability.

These changes collectively improve maintainability, clarity, and testability of the codebase.