Add simplified SDK client API and comprehensive documentation

- Create DeltaGliderClient with user-friendly interface
- Add create_client() factory function with sensible defaults
- Implement UploadSummary dataclass with helpful properties
- Expose simplified API through main package
- Add comprehensive SDK documentation under docs/sdk/:
  - Getting started guide with installation and examples
  - Complete API reference documentation
  - Real-world usage examples for 8 common scenarios
  - Architecture deep dive explaining how DeltaGlider works
  - Automatic documentation generation scripts
- Update CONTRIBUTING.md with SDK documentation guidelines
- All tests pass and code quality checks succeed

🤖 Generated with [Claude Code](https://claude.ai/code)

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

docs/sdk/Makefile

@@ -0,0 +1,36 @@
+# Makefile for DeltaGlider SDK Documentation
+
+.PHONY: all clean generate serve
+
+# Default target
+all: generate
+
+# Generate documentation
+generate:
+	@echo "Generating SDK documentation..."
+	python generate_docs.py
+	@echo "Documentation generated successfully!"
+
+# Clean generated files
+clean:
+	@echo "Cleaning generated documentation..."
+	rm -f generated_api.md module_index.json
+	@echo "Clean complete!"
+
+# Serve documentation locally (requires Python http.server)
+serve:
+	@echo "Starting documentation server at http://localhost:8000/docs/sdk/"
+	cd ../.. && python -m http.server 8000
+
+# Install documentation dependencies
+install-deps:
+	pip install pdoc3 sphinx sphinx-rtd-theme
+
+# Generate full HTML documentation with pdoc
+html:
+	pdoc3 --html --output-dir html ../../src/deltaglider
+
+# Generate with Sphinx (future enhancement)
+sphinx:
+	@echo "Sphinx documentation generation not yet configured"
+	@echo "Run 'make install-deps' then 'sphinx-quickstart' to set up"