fix(py): add PyPI metadata so the project page has a description

The 0.0.2 wheel went up with no `description`, no long-description
README, and no project URLs because pyproject.toml only carried name +
version. Add a one-line summary, point `readme` at the existing
sqlshield-py/README.md, declare authors, license, keywords, project
URLs, and a fuller classifier set so `pip show` and the PyPI project
page render properly.

Author: davidsmfreire

sqlshield-py/pyproject.toml

@@ -4,13 +4,38 @@ build-backend = "maturin"
 
 [project]
 name = "sqlshield-py"
+description = "Schema-aware SQL linter for raw SQL embedded in Python (and other) source code — no database required."
+readme = "README.md"
+license = { text = "MIT" }
+authors = [{ name = "David Freire", email = "work@davidfrei.re" }]
 requires-python = ">=3.8"
+keywords = ["sql", "linter", "static-analysis", "schema", "postgres", "mysql", "sqlite"]
 classifiers = [
+    "Development Status :: 3 - Alpha",
+    "Intended Audience :: Developers",
+    "License :: OSI Approved :: MIT License",
+    "Operating System :: OS Independent",
     "Programming Language :: Rust",
+    "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",
+    "Programming Language :: Python :: 3.13",
     "Programming Language :: Python :: Implementation :: CPython",
     "Programming Language :: Python :: Implementation :: PyPy",
+    "Topic :: Database",
+    "Topic :: Software Development :: Quality Assurance",
+    "Topic :: Software Development :: Testing",
 ]
 dynamic = ["version"]
 
+[project.urls]
+Homepage = "https://github.com/davidsmfreire/sqlshield"
+Repository = "https://github.com/davidsmfreire/sqlshield"
+Issues = "https://github.com/davidsmfreire/sqlshield/issues"
+Changelog = "https://github.com/davidsmfreire/sqlshield/blob/main/CHANGELOG.md"
+
 [tool.maturin]
 features = ["pyo3/extension-module"]