Add initial implementation of CalMiner with project structure, environment setup, and core features

- Create .env.example for environment variables
- Update README with project structure and development setup instructions
- Implement FastAPI application with API routes for scenarios and parameters
- Add database models for scenarios, parameters, and simulation results
- Introduce validation middleware for JSON requests
- Create services for running simulations and generating reports
- Add testing strategy and directory structure in documentation

docs/testing.md

@@ -27,3 +27,48 @@ CalMiner will use a combination of unit, integration, and end-to-end tests to en
 - Unit: `pytest tests/unit/`
 - Integration: `pytest tests/integration/`
 - All: `pytest`
+
+## Test Directory Structure
+
+Organize tests under the `tests/` directory mirroring the application structure:
+
+```bash
+tests/
+  unit/
+    test_<module>.py
+  integration/
+    test_<endpoint>.py
+  fixtures/
+    conftest.py
+```
+
+## Writing Tests
+
+- Name tests with the `test_` prefix.
+- Group related tests in classes or modules.
+- Use descriptive assertion messages.
+
+## Fixtures and Test Data
+
+- Define reusable fixtures in `tests/fixtures/conftest.py`.
+- Use temporary in-memory databases or isolated schemas for DB tests.
+- Load sample data via fixtures for consistent test environments.
+
+## Mocking and Dependency Injection
+
+- Use `unittest.mock` to mock external dependencies.
+- Inject dependencies via function parameters or FastAPI's dependency overrides in tests.
+
+## Code Coverage
+
+- Install `pytest-cov` to generate coverage reports.
+- Run with coverage: `pytest --cov=calminer --cov-report=html`.
+- Ensure coverage meets the 80% threshold.
+
+## CI Integration
+
+- Configure GitHub Actions workflow in `.github/workflows/ci.yml` to:
+  - Install dependencies
+  - Run `pytest` with coverage
+  - Fail on coverage <80%
+  - Upload coverage artifact