cmake: fix Windows build support

On Windows, shared libraries (DLLs) require an import library (.lib)
for linking, and the DLL itself is placed in bin/ rather than lib/ by
the Zig build. The CMake wrapper was missing IMPORTED_IMPLIB on the
shared imported target, causing link failures, and assumed the shared
library was always in lib/.

Add GHOSTTY_VT_IMPLIB for the import library name, set IMPORTED_IMPLIB
on the ghostty-vt target, and fix the shared library path to use bin/
on Windows. Install the DLL and PDB to bin/ and the import library to
lib/ following standard Windows conventions. Apply the same fixes to
ghostty-vt-config.cmake.in for the find_package path.

.github/workflows/test.yml

@@ -87,6 +87,7 @@ jobs:
       - build-dist
       - build-examples-zig
       - build-examples-cmake
+      - build-examples-cmake-windows
       - build-cmake
       - build-flatpak
       - build-libghostty-vt
@@ -263,6 +264,30 @@ jobs:
           nix develop -c cmake -B build -DFETCHCONTENT_SOURCE_DIR_GHOSTTY=${{ github.workspace }}
           nix develop -c cmake --build build
 
+  build-examples-cmake-windows:
+    strategy:
+      fail-fast: false
+      matrix:
+        dir: ${{ fromJSON(needs.list-examples.outputs.cmake) }}
+    name: Example ${{ matrix.dir }} (Windows)
+    runs-on: windows-2025
+    continue-on-error: true
+    timeout-minutes: 45
+    needs: [test, list-examples]
+    steps:
+      - name: Checkout code
+        uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
+
+      - name: Install zig
+        uses: mlugg/setup-zig@d1434d08867e3ee9daa34448df10607b98908d29 # v2.2.1
+
+      - name: Build Example
+        shell: pwsh
+        run: |
+          cd example/${{ matrix.dir }}
+          cmake -B build -DFETCHCONTENT_SOURCE_DIR_GHOSTTY=${{ github.workspace }}
+          cmake --build build
+
   build-cmake:
     runs-on: namespace-profile-ghostty-sm
     needs: test