fix(ci): validate private .NET SDK

.gitea/workflows/ci-deploy.yml

@@ -21,7 +21,16 @@ jobs:
         # dir via dotnet-install.sh and retry once on failure, mirroring the
         # npm ci / NuGet retries elsewhere in this workflow.
         run: |
-          if [ -x "$HOME/.dotnet/dotnet" ] && "$HOME/.dotnet/dotnet" --list-sdks | grep -q '^9\.'; then
+          export DOTNET_ROOT="$HOME/.dotnet"
+          export PATH="$DOTNET_ROOT:$PATH"
+
+          validate_sdk() {
+            [ -x "$DOTNET_ROOT/dotnet" ] \
+              && "$DOTNET_ROOT/dotnet" --list-sdks | grep -q '^9\.' \
+              && "$DOTNET_ROOT/dotnet" --info >/dev/null
+          }
+
+          if validate_sdk; then
             echo "Reusing valid runner-local .NET 9 SDK."
           else
             install() {
@@ -31,14 +40,15 @@ jobs:
                 feed_args=(--azure-feed "$feed")
               fi
               curl -fsSL https://dot.net/v1/dotnet-install.sh -o /tmp/dotnet-install.sh
-              rm -rf "$HOME/.dotnet"
-              bash /tmp/dotnet-install.sh --channel 9.0 --install-dir "$HOME/.dotnet" "${feed_args[@]}"
+              rm -rf "$DOTNET_ROOT"
+              bash /tmp/dotnet-install.sh --channel 9.0 --install-dir "$DOTNET_ROOT" "${feed_args[@]}"
+              validate_sdk
             }
             install || ( echo "dotnet install failed ($?) — retrying from alternate Microsoft CDN..." \
               && install https://dotnetcli.azureedge.net/dotnet )
           fi
-          echo "$HOME/.dotnet" >> "$GITHUB_PATH"
-          "$HOME/.dotnet/dotnet" --info
+          echo "$DOTNET_ROOT" >> "$GITHUB_PATH"
+          "$DOTNET_ROOT/dotnet" --info
 
       - name: Setup Node
         uses: actions/setup-node@v4