test: update test suite for OmegaConf config system

- Add tests/conftest.py with make_settings() helper that maps legacy config
  parameter names to new nested OmegaConf structure
- Update all test files to use the conftest fixture
- All 73 tests now pass with new config system
- Maintains backward compatibility via Settings class properties

Also add AGENTS.md with comprehensive AI agent guidelines:
- Project overview and key technologies
- Directory structure reference
- Development workflow and common tasks
- Testing strategy and patterns
- CI/CD pipeline overview
- Common pitfalls and best practices
- Debugging guide for agents working on the project

.pre-commit-config.yaml

@@ -0,0 +1,18 @@
+repos:
+  - repo: local
+    hooks:
+      - id: ruff-check
+        name: ruff check
+        entry: ruff check
+        language: system
+        types: [python]
+        stages: [commit]
+
+      - id: pytest
+        name: pytest
+        entry: pytest
+        language: system
+        types: [python]
+        pass_filenames: false
+        always_run: true
+        stages: [commit]