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/start.sh

@@ -0,0 +1,77 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+log() { echo "[start] $(date -Is) $*"; }
+abort() { echo "[start] ERROR: $*" >&2; exit 1; }
+
+# Defaults
+: "${APP_PORT:=8080}"
+: "${JENKINS_HOME:=/app/data/jenkins_home}"
+
+log "Starting Jenkins CI/CD on port ${APP_PORT}"
+
+# Ensure Jenkins home directory exists and is writable
+mkdir -p "${JENKINS_HOME}"
+chown -R cloudron:cloudron /app/data || true
+
+# Set Jenkins environment variables
+export JENKINS_HOME="${JENKINS_HOME}"
+export JENKINS_OPTS="--httpPort=${APP_PORT} --httpListenAddress=0.0.0.0"
+
+# Configure Jenkins for Cloudron
+log "Configuring Jenkins for Cloudron environment"
+
+# Create basic Jenkins configuration if not exists
+if [[ ! -f "${JENKINS_HOME}/config.xml" ]]; then
+    log "Creating initial Jenkins configuration"
+    mkdir -p "${JENKINS_HOME}"
+    
+    # Create basic config.xml for Jenkins
+    cat > "${JENKINS_HOME}/config.xml" <<'XML'
+<?xml version='1.1' encoding='UTF-8'?>
+<hudson>
+  <version>2.450</version>
+  <numExecutors>2</numExecutors>
+  <mode>NORMAL</mode>
+  <useSecurity>true</useSecurity>
+  <authorizationStrategy class="hudson.security.FullControlOnceLoggedInAuthorizationStrategy"/>
+  <securityRealm class="hudson.security.HudsonPrivateSecurityRealm">
+    <disableSignup>true</disableSignup>
+  </securityRealm>
+  <disableRememberMe>false</disableRememberMe>
+  <projectNamingStrategy class="jenkins.model.ProjectNamingStrategy$DefaultProjectNamingStrategy"/>
+  <workspaceDir>${JENKINS_HOME}/workspace/${ITEM_FULLNAME}</workspaceDir>
+  <buildsDir>${JENKINS_HOME}/builds/${ITEM_FULLNAME}</buildsDir>
+  <markupFormatter class="hudson.markup.RawHtmlMarkupFormatter" plugin="antisamy-markup-formatter@3.1"/>
+  <jdks/>
+  <viewsTabBar class="hudson.views.DefaultViewsTabBar"/>
+  <myViewsTabBar class="hudson.views.DefaultMyViewsTabBar"/>
+  <clouds/>
+  <slaves/>
+  <scm class="hudson.scm.NullSCM"/>
+  <views>
+    <hudson.model.AllView>
+      <owner class="hudson" reference="../../.."/>
+      <name>all</name>
+      <filterExecutors>false</filterExecutors>
+      <filterQueue>false</filterQueue>
+      <properties class="hudson.model.View$PropertyList"/>
+    </hudson.model.AllView>
+  </views>
+  <primaryView>all</primaryView>
+  <slaveAgentPort>50000</slaveAgentPort>
+  <disabledAgentProtocols>
+    <string>JNLP-connect</string>
+    <string>JNLP2-connect</string>
+  </disabledAgentProtocols>
+  <label></label>
+  <nodeProperties/>
+  <globalNodeProperties/>
+</hudson>
+XML
+fi
+
+# Start Jenkins
+log "Starting Jenkins WAR file"
+exec java -jar /app/pkg/jenkins.war ${JENKINS_OPTS}
+