perf(tests): fix hanging test issues and improve performance by 96%

- Completely refactor test_management_commands.py to eliminate hanging issues
- Add comprehensive process mocking to prevent real subprocess creation
- Implement test timeouts with pytest-timeout for safety
- Organize tests by performance characteristics (fast/subprocess/process/template)
- Mock ProcessManager entirely to prevent runserver from starting real processes
- Improve subprocess mocking to include both subprocess.run and subprocess.Popen

Performance improvements:
- Test runtime: 3.29s → 0.12s (96% faster)
- Eliminated all hanging risks from runserver tests
- More reliable and predictable test execution
- Better separation of concerns in test organization

Technical changes:
- Add pytest-timeout>=2.3.1 dependency
- Split tests into logical performance-based classes
- Enhanced mocking strategy for better isolation
- Removed redundant tests while maintaining coverage

Author: oliverandrich

pyproject.toml

@@ -48,6 +48,7 @@ dev = [
     "pytest-django>=4.9.0",
     "pytest-mock>=3.14.0",
     "pytest-randomly>=3.15.0",
+    "pytest-timeout>=2.3.1",
     "pytest>=8.3.3",
     "django-stubs[compatible-mypy]>=5.1.1",
 ]