ci: add Windows to build matrix and integration tests

- Add windows-latest to OS matrix with x86_64-pc-windows-msvc target
- Add dedicated Windows integration test job
- Verify Windows executable functionality
- Ensure cross-platform compatibility testing

This ensures Windows build issues are caught early in CI/CD pipeline.

.github/workflows/build.yml

@@ -3,7 +3,7 @@ name: Build
 on:
   workflow_dispatch:
   push:
-    branches: [ main ]
+    branches: [main]
   pull_request:
 
 jobs:
@@ -12,12 +12,14 @@ jobs:
     runs-on: ${{ matrix.os }}
     strategy:
       matrix:
-        os: [ubuntu-latest, macos-latest]
+        os: [ubuntu-latest, macos-latest, windows-latest]
         include:
           - os: ubuntu-latest
             target: x86_64-unknown-linux-gnu
           - os: macos-latest
             target: x86_64-apple-darwin
+          - os: windows-latest
+            target: x86_64-pc-windows-msvc
 
     steps:
       - name: Checkout code