Add conflict detection workflow for PRs

This workflow scans pull requests for overlapping file changes using the jules-merge tool.

Author: LeanBitLab

.github/workflows/jules-merge-conflicts.yml

@@ -0,0 +1,23 @@
+# Generated by @google/jules-fleet init
+# This workflow scans PRs for overlapping file changes.
+name: Conflict Detection
+
+on:
+  pull_request:
+    branches: [main]
+
+permissions:
+  contents: read
+  pull-requests: read
+
+jobs:
+  scan-overlaps:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+        with:
+          fetch-depth: 0
+
+      - name: Scan for overlapping changes
+        run: |
+          npx -y --package=@google/jules-merge jules-merge scan --json '{"prs":[${{ github.event.pull_request.number }}],"repo":"${{ github.repository }}","base":"${{ github.event.pull_request.base.ref }}"}'