Update GitHub Actions workflows to install requirements and enforce numpy dependency

- Add `pip install -r requirements.txt` to all workflows for consistent dependency management
- Specify `numpy>=1.19.0` as a core dependency in `setup.py` and `requirements.txt`

Author: bnbailey-psl

.github/workflows/test-matrix.yml

@@ -43,6 +43,7 @@ jobs:
       run: |
         python -m pip install --upgrade pip
         pip install pytest pytest-cov pytest-xdist
+        pip install -r requirements.txt
         pip install -e .
 
     - name: Verify PyHelios installation and platform detection

.github/workflows/test-quick.yml

@@ -26,6 +26,7 @@ jobs:
       run: |
         python -m pip install --upgrade pip
         pip install pytest
+        pip install -r requirements.txt
         pip install -e .
 
     - name: Quick smoke test

.github/workflows/test-required.yml

@@ -32,6 +32,7 @@ jobs:
       run: |
         python -m pip install --upgrade pip
         pip install pytest
+        pip install -r requirements.txt
         pip install -e .
 
     - name: Verify PyHelios installation
@@ -120,6 +121,7 @@ jobs:
       run: |
         python -m pip install --upgrade pip
         pip install pytest
+        pip install -r requirements.txt
         pip install -e .
 
     - name: Build native Helios libraries

requirements.txt

@@ -1,2 +1 @@
-
-
+numpy>=1.19.0

setup.py

@@ -85,7 +85,7 @@ def get_long_description():
 
     # Dependencies
     install_requires=[
-        # Core dependencies - minimal for maximum compatibility
+        'numpy>=1.19.0',  # Core dependency for PyHelios data structures
     ],
     extras_require={
         'dev': read_dev_requirements(),