Add initial implementation of PolinRider malware scanner

- Introduced core files including Dockerfile, action.yml, and entry point script (bin/polinrider.js) for the PolinRider malware scanner.
- Created configuration files: .env.example, .gitignore, and .npmrc for environment setup and dependency management.
- Added CI workflows for testing, building, and releasing the action, along with examples for usage in GitHub Actions.
- Implemented a README.md to provide documentation on usage, features, and setup instructions.
- Included necessary scripts for building the action and handling security measures during execution.
- Established a structured directory for reports and workspace management within Docker.
- Ensured all files are set up for a secure and efficient scanning process of GitHub repositories for PolinRider malware.

examples/pr-scheduled.yml

@@ -0,0 +1,23 @@
+# Scan the default branch on a schedule and open a cleanup PR if anything is
+# found. Good for fork PRs / protected branches where commit-back can't push.
+name: PolinRider weekly scan
+on:
+  schedule:
+    - cron: "0 6 * * 1" # Mondays 06:00 UTC
+  workflow_dispatch:
+
+permissions:
+  contents: write # create the cleanup branch
+  pull-requests: write # open the PR
+
+jobs:
+  scan:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - uses: RMSoft-ltd/polinrider-cleanup@v1
+        with:
+          mode: pr
+          token: ${{ secrets.GITHUB_TOKEN }}
+          # auto-merge: true        # respects branch protection
+          # merge-method: squash