ci: run Windows CMake examples after building

Add a "Run Example" step to the build-examples-cmake-windows job
so that each CMake example is executed after it is built, verifying
the resulting binaries actually work. The executable name is derived
from the matrix directory name by replacing hyphens with underscores,
matching the project convention.

.github/workflows/test.yml

@@ -288,6 +288,14 @@ jobs:
           cmake -B build -DFETCHCONTENT_SOURCE_DIR_GHOSTTY=${{ github.workspace }}
           cmake --build build
 
+      - name: Run Example
+        shell: pwsh
+        run: |
+          $name = "${{ matrix.dir }}" -replace '-','_'
+          $exe = "example/${{ matrix.dir }}/build/Debug/${name}.exe"
+          if (!(Test-Path $exe)) { $exe = "example/${{ matrix.dir }}/build/${name}.exe" }
+          & $exe
+
   build-cmake:
     runs-on: namespace-profile-ghostty-sm
     needs: test