Add integration tests to CI workflow for pull requests

- Separate unit tests from integration tests in CI
- Add new integration-test job that runs only on PRs
- Use Python 3.12 specifically for integration tests
- Decrypt NUTRIENT_DWS_API_KEY secret and create integration_config.py
- Run integration tests against live Nutrient DWS API

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

Author: msch-nutrient

.github/workflows/ci.yml

@@ -43,8 +43,8 @@ jobs:
     - name: Run type checking with mypy
       run: python -m mypy --python-version=${{ matrix.python-version }} src tests
 
-    - name: Run tests with pytest
-      run: python -m pytest -v --cov=nutrient_dws --cov-report=xml --cov-report=term
+    - name: Run unit tests with pytest
+      run: python -m pytest tests/unit/ -v --cov=nutrient_dws --cov-report=xml --cov-report=term
 
     - name: Upload coverage to Codecov
       uses: codecov/codecov-action@v4
@@ -55,6 +55,40 @@ jobs:
         name: codecov-umbrella
         fail_ci_if_error: false
 
+  integration-test:
+    runs-on: ubuntu-latest
+    if: github.event_name == 'pull_request'
+    
+    steps:
+    - uses: actions/checkout@v4
+
+    - name: Set up Python 3.12
+      uses: actions/setup-python@v5
+      with:
+        python-version: '3.12'
+
+    - name: Cache pip dependencies
+      uses: actions/cache@v4
+      with:
+        path: ~/.cache/pip
+        key: ${{ runner.os }}-pip-${{ hashFiles('pyproject.toml') }}
+        restore-keys: |
+          ${{ runner.os }}-pip-
+
+    - name: Install dependencies
+      run: |
+        python -m pip install --upgrade pip
+        pip install -e ".[dev]"
+
+    - name: Create integration config with API key
+      run: |
+        echo 'API_KEY = "${{ secrets.NUTRIENT_DWS_API_KEY }}"' > tests/integration/integration_config.py
+      env:
+        NUTRIENT_DWS_API_KEY: ${{ secrets.NUTRIENT_DWS_API_KEY }}
+
+    - name: Run integration tests
+      run: python -m pytest tests/integration/ -v
+
   build:
     runs-on: ubuntu-latest
     needs: test