feat(jenkins): add Jenkins CI/CD Platform Cloudron package

- Complete Jenkins package with Java 17 and WAR file download
- Proper CloudronManifest.json with correct metadata
- Custom start.sh script with Jenkins configuration
- Health check endpoint configured for /login
- Follows KNELCloudron- naming convention
- Added comprehensive packaging shortlist with 56 applications prioritized by phase

CloudronPackages/Jenkins/README.md

@@ -0,0 +1,33 @@
+# Package Template for Cloudron Apps
+
+This is a minimal template to package an application for Cloudron.
+
+## Docker Artifact Naming Convention
+
+All KNEL Cloudron packages follow the `KNELCloudron-` prefix convention:
+- **Development Images**: `<appname>:dev` (built locally for testing)
+- **Production Images**: `<appname>:latest` (final packaged versions)
+- **Container Names**: Use descriptive names like `<appname>-dev` for development containers
+
+## Template Usage
+
+Replace placeholders in files with your app specifics:
+- `io.knel.jenkins` (e.g., com.example.myapp)
+- `Jenkins CI/CD` (human name)
+- `8080` (default internal app port)
+- `5.0.0` (Cloudron base image tag, e.g., 5.0.0)
+
+Files
+- `CloudronManifest.json` – base manifest
+- `Dockerfile` – uses cloudron/base, non-root user, healthcheck
+- `start.sh` – startup script with addon detection examples
+- `nginx.conf` (optional) – example reverse proxy
+- `supervisord.conf` (optional) – process manager example
+- `config.yaml` (optional) – sample app config
+- `logo.png` – add your 512x512 PNG icon here (not provided in template)
+
+Usage
+1. Create a new package from this template using `scripts/new-package.sh`:
+   `scripts/new-package.sh MyApp --id com.example.myapp --title "My App" --port 3000`
+2. Adjust Dockerfile and start.sh to run your app.
+3. Build and test locally; then commit and push.