test: add agent test coverage and standardize test suite (#2051)

- Add 104 comprehensive tests for agent system
- Integrate agent tests into CI/CD pipeline
- Standardize tests with @pytest.mark.unit markers
- Fix cross-platform path compatibility
- Clean up unused imports and dependencies

pytest.ini

@@ -0,0 +1,20 @@
+[pytest]
+testpaths = tests
+python_files = test_*.py
+python_classes = Test*
+python_functions = test_*
+addopts = 
+    -v
+    --strict-markers
+    --tb=short
+    --cov=application
+    --cov-report=html
+    --cov-report=term-missing
+    --cov-report=xml
+markers =
+    unit: Unit tests
+    integration: Integration tests
+    slow: Slow running tests
+filterwarnings =
+    ignore::DeprecationWarning
+    ignore::PendingDeprecationWarning