ci(prerelease): build Windows installers on windows-latest (#586)

The prerelease Windows matrix entries used os: ubuntu-latest, but the
'Install Inno Setup' / 'Create Windows installer' steps require a real
Windows runner (Chocolatey + ISCC.exe). On Ubuntu, 'choco' does not
exist, so the v0.37.0-rc.1 prerelease build (run 26926147427) failed:

  choco: The term 'choco' is not recognized as a name of a cmdlet...
  ##[error]Process completed with exit code 1.

Switch the two Windows matrix entries to windows-latest with cgo: "1",
matching the proven release.yml configuration. Because the shared build
steps now run on a Windows host (default shell pwsh), add shell: bash to
the bash-syntax steps ('Copy frontend dist', 'Build binary and create
archives') and use PowerShell Compress-Archive for the Windows .zip
(the 'zip' command is unavailable in Git-bash on windows-latest) — all
mirroring release.yml. macOS/Linux build behavior is unchanged.

Author: Dumbris

.github/workflows/prerelease.yml

@@ -33,16 +33,16 @@ jobs:
             cgo: "0"
             name: mcpproxy-linux-arm64
             archive_format: tar.gz
-          - os: ubuntu-latest
+          - os: windows-latest
             goos: windows
             goarch: amd64
-            cgo: "0"
+            cgo: "1"
             name: mcpproxy-windows-amd64.exe
             archive_format: zip
-          - os: ubuntu-latest
+          - os: windows-latest
             goos: windows
             goarch: arm64
-            cgo: "0"
+            cgo: "1"
             name: mcpproxy-windows-arm64.exe
             archive_format: zip
           - os: macos-15
@@ -97,6 +97,7 @@ jobs:
         run: cd frontend && npm run build
 
       - name: Copy frontend dist to embed location
+        shell: bash
         run: |
           rm -rf web/frontend
           mkdir -p web/frontend
@@ -182,6 +183,7 @@ jobs:
 
 
       - name: Build binary and create archives
+        shell: bash
         env:
           CGO_ENABLED: ${{ matrix.cgo }}
           GOOS: ${{ matrix.goos }}
@@ -406,7 +408,12 @@ jobs:
 
           if [ "${{ matrix.archive_format }}" = "zip" ]; then
             # Create only versioned archive (no latest for prereleases)
-            zip "${ARCHIVE_BASE}.zip" ${CLEAN_BINARY}
+            if [ "${{ matrix.goos }}" = "windows" ]; then
+              # Use PowerShell Compress-Archive on Windows since zip command isn't available
+              powershell -Command "Compress-Archive -Path '${CLEAN_BINARY}' -DestinationPath '${ARCHIVE_BASE}.zip'"
+            else
+              zip "${ARCHIVE_BASE}.zip" ${CLEAN_BINARY}
+            fi
           else
             # Create only versioned archive (no latest for prereleases)
             tar -czf "${ARCHIVE_BASE}.tar.gz" ${CLEAN_BINARY}