feat: add Python bindings via PyO3

Expose the pdf-inspector Rust library as a Python package using PyO3 + maturin.
Python users can now `pip install` and use `import pdf_inspector` for PDF
classification, text extraction, and markdown conversion with native Rust speed.

Adds:
- src/python.rs: PyO3 bindings (process_pdf, detect_pdf, extract_text, etc.)
- pyproject.toml: maturin build configuration
- pdf_inspector.pyi: type stubs for IDE support
- tests/test_python.py: 21 pytest tests covering all Python API functions
- examples/basic_usage.py: example script demonstrating all features
- Updated README with Python quick start and API reference

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

pyproject.toml

@@ -0,0 +1,21 @@
+[build-system]
+requires = ["maturin>=1.0,<2.0"]
+build-backend = "maturin"
+
+[project]
+name = "pdf-inspector"
+version = "0.1.0"
+description = "Fast PDF inspection, classification, and text extraction with smart scanned vs text-based detection"
+license = { text = "MIT" }
+requires-python = ">=3.8"
+classifiers = [
+    "Programming Language :: Rust",
+    "Programming Language :: Python :: Implementation :: CPython",
+    "Programming Language :: Python :: 3",
+    "License :: OSI Approved :: MIT License",
+    "Operating System :: OS Independent",
+    "Topic :: Text Processing",
+]
+
+[tool.maturin]
+features = ["python"]