add security tooling and development workflow

- ruff for linting and formatting
- bandit for security scanning
- mypy for type checking
- pip-audit for dependency vulnerabilities
- Makefile with lint/format/security/test targets

requirements-dev.txt

@@ -0,0 +1,17 @@
+# Development and CI dependencies
+# Install: pip install -r requirements-dev.txt
+
+# Testing
+pytest>=8.0
+pytest-cov>=4.1
+
+# Code quality
+ruff>=0.8
+mypy>=1.8
+
+# Security analysis
+bandit>=1.7
+pip-audit>=2.6
+
+# Type stubs
+types-requests>=2.31