fix: dynamic chain processor startup and Python SDK build dependencies

- Start chain processor when new chains are dynamically registered,
  fixing TestQuantumSecurityForAllChains test failure
- Add pyproject.toml with Cython build dependency for proper PEP 517 builds
- Simplify SDK verification workflow Python install step

pkg/python/pyproject.toml

@@ -0,0 +1,33 @@
+[build-system]
+requires = ["setuptools>=64", "wheel", "cython>=3.0", "numpy>=1.20.0"]
+build-backend = "setuptools.build_meta"
+
+[project]
+name = "lux-consensus"
+version = "1.22.0"
+description = "Python bindings for Lux Consensus C library with optional MLX GPU acceleration"
+authors = [{name = "Lux Industries Inc."}]
+readme = "README.md"
+requires-python = ">=3.8"
+license = {text = "Apache-2.0"}
+classifiers = [
+    "Development Status :: 4 - Beta",
+    "Intended Audience :: Developers",
+    "License :: OSI Approved :: Apache Software License",
+    "Programming Language :: Python :: 3",
+    "Programming Language :: Python :: 3.8",
+    "Programming Language :: Python :: 3.9",
+    "Programming Language :: Python :: 3.10",
+    "Programming Language :: Python :: 3.11",
+    "Programming Language :: Python :: 3.12",
+]
+dependencies = [
+    "numpy>=1.20.0",
+]
+
+[project.optional-dependencies]
+mlx = ["mlx>=0.0.1"]
+dev = ["pytest>=7.0.0", "pytest-benchmark>=4.0.0", "pytest-cov>=4.0.0"]
+
+[tool.setuptools]
+packages = ["lux_consensus"]