feat: add multi-OS testing to CI for world-class quality control

Added matrix strategy to test on multiple operating systems:
- Ubuntu Latest (Linux)
- macOS Latest
- Windows Latest

Benefits:
- Ensures cross-platform compatibility
- Catches OS-specific bugs early
- World-class quality control
- fail-fast: false continues testing other OS even if one fails

CI now runs 3x the tests (one per OS) for maximum confidence.

Author: nolindnaidoo

.github/workflows/ci.yml

@@ -8,7 +8,12 @@ on:
 
 jobs:
   ci:
-    runs-on: ubuntu-latest
+    name: CI on ${{ matrix.os }}
+    runs-on: ${{ matrix.os }}
+    strategy:
+      matrix:
+        os: [ubuntu-latest, macos-latest, windows-latest]
+      fail-fast: false
 
     steps:
       - uses: actions/checkout@v4