fix: resolve CI linting violations

- Fixed import sorting in cli.py, __main__.py, detectors/__init__.py, base.py, python.py, rust.py, openapi.py, models/__init__.py
- Removed unused imports (sys, asyncio, Observer, Text, Parameter, ParameterIn, HTTPMethod, DocConfig, List, Optional)
- Removed trailing whitespace from blank lines
- Split lines exceeding 100 characters
- Added missing __init__ docstrings in generators and static/templates packages

src/docgen/templates/__init__.py

@@ -0,0 +1 @@
+{"""Templates package."""