feat: Add WIP prefix to PRs with bot comment

Co-authored-by: matiss <matiss@mja.lv>

.github/workflows/pr-wip-prefix.yml

@@ -0,0 +1,43 @@
+name: Add WIP prefix to PRs
+
+on:
+  pull_request:
+    types: [opened]
+
+permissions:
+  contents: read
+  pull-requests: write
+  issues: write
+
+jobs:
+  add-wip-and-comment:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Add [WIP] prefix to PR title
+        id: wip
+        uses: actions/github-script@v7
+        with:
+          script: |
+            const title = context.payload.pull_request.title || '';
+            const number = context.payload.pull_request.number;
+            const { owner, repo } = context.repo;
+
+            const hasWip = /^\s*(\[\s*WIP\s*\]|WIP\b)/i.test(title);
+            let added = false;
+            if (!hasWip) {
+              const newTitle = `[WIP] ${title}`;
+              await github.rest.pulls.update({ owner, repo, pull_number: number, title: newTitle });
+              added = true;
+            }
+
+            core.setOutput('wip_added', String(added));
+
+      - name: Comment why WIP prefix was added
+        if: steps.wip.outputs.wip_added == 'true'
+        uses: peter-evans/create-or-update-comment@v3
+        with:
+          issue-number: ${{ github.event.pull_request.number }}
+          body: |
+            :wave: Hi! I have added a WIP prefix to the PR. Please remove it once the PR has all CI checks passed as green and once you are happy for a maintainer to review this PR. Thanks!
+            <!-- wip-prefix-comment -->
+