Bump minimal supported Python version to py3.11

[xsedla1o]

Python 3.9 has reached EOL and Python 3.10 EOL is approaching, so this branch bumps DP3’s supported/runtime baseline to Python 3.11 and modernizes the codebase/tooling accordingly.

Key changes

• Require Python 3.11 in packaging, Ruff/Black targets, Docker images, CI docs deploy, README, and docs.
• Apply Ruff/Black modernization for Python 3.11, including PEP 604 union types and related typing/import cleanup.
• Fix Python 3.11/runtime typing issues around dynamic API entity ID validation and MACAddress.
• Replace deprecated Pydantic APIs with current equivalents.
• Preserve /entity/{etype}/{eid}/set/{attr} behavior by explicitly parsing JSON request bodies.
• Add small typing cleanups for config defaults and task queue pyright compatibility.