Enable auto-merge for PRs targeting main/master and add Windows desktop workload to CI

.github/workflows/auto-merge.yml

@@ -0,0 +1,72 @@
+name: Auto-merge
+
+on:
+  pull_request:
+    types:
+      - opened
+      - reopened
+      - synchronize
+      - ready_for_review
+  check_suite:
+    types:
+      - completed
+  workflow_run:
+    workflows: ["CI"]
+    types:
+      - completed
+
+permissions:
+  contents: write
+  pull-requests: write
+
+jobs:
+  enable-auto-merge:
+    if: ${{ github.event.pull_request.draft == false || github.event_name != 'pull_request' }}
+    runs-on: ubuntu-latest
+    steps:
+      - name: Enable auto-merge for eligible PRs
+        uses: actions/github-script@v7
+        with:
+          script: |
+            const owner = context.repo.owner;
+            const repo = context.repo.repo;
+            const pr =
+              context.payload.pull_request ??
+              (context.payload.check_suite?.pull_requests?.[0] ?? null);
+
+            if (!pr) {
+              core.info("No pull request in event payload.");
+              return;
+            }
+
+            if (pr.draft) {
+              core.info(`PR #${pr.number} is draft; skipping auto-merge.`);
+              return;
+            }
+
+            const allowedBases = new Set(["main", "master"]);
+            if (!allowedBases.has(pr.base?.ref)) {
+              core.info(`PR #${pr.number} targets ${pr.base?.ref}; only main/master are auto-merged.`);
+              return;
+            }
+
+            if (pr.head?.repo?.fork) {
+              core.info(`PR #${pr.number} comes from a fork; skipping auto-merge.`);
+              return;
+            }
+
+            const mutation = `
+              mutation($prId: ID!) {
+                enablePullRequestAutoMerge(input: { pullRequestId: $prId, mergeMethod: SQUASH }) {
+                  pullRequest {
+                    number
+                    autoMergeRequest {
+                      enabledAt
+                    }
+                  }
+                }
+              }
+            `;
+
+            core.info(`Enabling auto-merge for PR #${pr.number}.`);
+            await github.graphql(mutation, { prId: pr.node_id });

.github/workflows/ci.yml

@@ -27,6 +27,9 @@ jobs:
           dotnet-version: '10.0.x'
           include-prerelease: true
 
+      - name: Install Windows Desktop workload
+        run: dotnet workload install windowsdesktop
+
       - name: Cache NuGet packages
         uses: actions/cache@v4
         with: