feat: improve Python packaging with proper pyproject.toml, dependenci…

[EclipseWraith]

Problem

The current pyproject.toml is minimal and has a critical issue: the runtime
dependencies (protobuf, redis) are listed only under [build-system].requires,
which means they are not installed when a user runs pip install. This causes
import errors when attempting to use the NSB Python client.

Changes

python/pyproject.toml

• Added protobuf and redis[hiredis] as runtime dependencies under [project].dependencies
• Added requires-python >= 3.7
• Added project metadata (description, license, authors, repository URLs)
• Added optional dev dependencies (pytest, pytest-asyncio) installable via pip install -e ".[dev]"
• Configured setuptools package discovery to include the proto subpackage

python/proto/init.py (new file)

• Marks the proto directory as a Python package, enabling import proto.nsb_pb2

python/README.md

• Replaced "Installable Python package coming soon" with working installation instructions
• Documented both pip install -e . (recommended) and manual setup (alternative) methods

Testing

• Verified pip install -e . succeeds on both Windows and Ubuntu 24.04 (WSL)
• Confirmed pip show nsb-client displays correct metadata and dependencies
• Confirmed protobuf and redis are automatically installed as dependencies