Fix PR #180 review issues: decorator stacking, lazy loading, and docs… - #181

…trings

Addresses all review comments on PR #180:

1. Fixed invalid @property/@classmethod decorator stacking (Comments #1 & #2)
   - Removed incompatible property/classmethod combinations
   - Replaced with proper @classmethod get_context() and set_context() methods
   - Maintains clean API while fixing Python decorator compatibility issues

2. Implemented true lazy loading to prevent --help arg capture
   - Changed _context from MadsciContext() to None as initial value
   - Context is now only created on first access via get_context()
   - This solves the original issue where module imports would capture CLI args

3. Fixed docstring formatting per PEP 257 (Comment #3)
   - Multi-line docstring with summary line
   - Blank line separator
   - Detailed description following PEP 257 standards

4. Updated all tests to use new classmethod API
   - All tests now call GlobalMadsciContext.get_context()
   - All tests now call GlobalMadsciContext.set_context()
   - Reduces verbose copy-modify-reassign patterns
   - All 7 tests pass successfully

The changes maintain backward compatibility while implementing proper
lazy initialization that solves the CLI argument capture issue.