fix: append .exe suffix to Windows binary download filename

The drone-ssh release publishes Windows assets with an .exe suffix
(e.g. drone-ssh-1.8.2-windows-amd64.exe), but entrypoint.sh built the
download filename without it, so every Windows runner failed with a 404
at the download step (ERR_DOWNLOAD_FAILED).

Append .exe when the detected platform is windows. This also keeps the
checksums.txt lookup working on Windows since entries match the exact
asset name. Add a windows-latest CI job that exercises the download,
checksum verification, and binary execution path.

Fixes #417

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

.github/workflows/main.yml

@@ -793,6 +793,20 @@ jobs:
             echo "Output contains 'True'"
           fi
 
+  windows-binary-download:
+    runs-on: windows-latest
+    steps:
+      - name: Checkout code
+        uses: actions/checkout@v7
+
+      - name: test binary download and checksum verification
+        shell: bash
+        run: |
+          export GITHUB_ACTION_PATH="$PWD"
+          export INPUT_CURL_INSECURE=false
+          export INPUT_CAPTURE_STDOUT=false
+          ./entrypoint.sh --help
+
   testing-script-error:
     runs-on: ubuntu-latest
     steps:

entrypoint.sh

@@ -39,6 +39,10 @@ function detect_client_info() {
 detect_client_info
 DOWNLOAD_URL_PREFIX="${DRONE_SSH_RELEASE_URL}/v${DRONE_SSH_VERSION}"
 CLIENT_BINARY="drone-ssh-${DRONE_SSH_VERSION}-${CLIENT_PLATFORM}-${CLIENT_ARCH}"
+# Windows release assets are published with an .exe suffix
+if [[ "${CLIENT_PLATFORM}" == "windows" ]]; then
+  CLIENT_BINARY="${CLIENT_BINARY}.exe"
+fi
 TARGET="${GITHUB_ACTION_PATH}/${CLIENT_BINARY}"
 
 # Check if binary already exists and is executable (caching)