Refactor repository structure for CICS TS V5.5 standard layout

[ayushikumari3]

Module renames:

• cics-java-liberty-jdbc-web → cics-java-liberty-jdbc-app
• cics-java-liberty-jdbc-bundle → cics-java-liberty-jdbc-cicsbundle
• etc/eclipse_projects/com.ibm.cicsdev.jdbc.web.cicsbundle → cics-java-liberty-jdbc-cicsbundle-eclipse (root level)

Build configuration:

• Add gradle.properties with java_version=8 and toolchain auto-provisioning
• Add settings.gradle with foojay toolchain resolver plugin
• Add root build.gradle with allprojects group/version/repositories
• Update -app/build.gradle: Java toolchain, wtp block (jst.web 3.1, contextPath), war archiveFileName
• Update -cicsbundle/build.gradle: CICS Bundle Plugin 1.0.8, new-line brace style
• Update root pom.xml: https schema, updated module names, pluginManagement for maven-compiler-plugin 3.13.0 and maven-war-plugin 3.4.0
• Update -app/pom.xml: artifactId rename, finalName, remove explicit plugin version
• Update -cicsbundle/pom.xml: artifactId rename, plugin 1.0.8, sibling dep rename

Wrappers:

• Gradle wrapper: 8.6 → 8.14.4
• Maven wrapper: 3.6.3 → 3.9.12 (only-script type)

Config:

• server.xml: jsp-2.3 → servlet-3.1
• type2.xml: add type="javax.sql.DataSource"
• web.xml: display-name updated
• Add ibm-web-ext.xml with context-root uri="cics-java-liberty-jdbc"

Eclipse metadata:

• Root: add .classpath (JavaSE-1.8), canonical .settings/org.eclipse.buildship.core.prefs, org.eclipse.jdt.core.prefs (Java 8, no release flag)
• -app: rename .project (cics-java-liberty-jdbc-app), update .classpath (CICS Liberty Libraries V.55/JEE_V7_R0, Gradle+M2E containers), canonical .settings/org.eclipse.buildship.core.prefs, org.eclipse.jdt.core.prefs, org.eclipse.wst.common.component (context-root), org.eclipse.wst.common.project.facet.core.xml (jst.web 3.1)
• -cicsbundle: rename .project (cics-java-liberty-jdbc-cicsbundle), canonical .settings/org.eclipse.buildship.core.prefs
• -cicsbundle-eclipse: rename .project (cics-java-liberty-jdbc-cicsbundle-eclipse,
  bundleID=cics-java-liberty-jdbc-bundle), update META-INF/cics.xml, rename warbundle to cics-java-liberty-jdbc-app.warbundle (symbolicname=cics-java-liberty-jdbc-app), canonical .settings/org.eclipse.core.resources.prefs

CI/CD:

• Replace java.yaml with build.yaml: 4-job matrix (build-gradle, build-gradlew, build-maven, build-mvnw), workflow-level permissions: contents: read, check-copyright with job-level write permissions and create-pull-request guard
• Add cleanup-old-runs.yaml using Mattraks/delete-workflow-runs@v2
• Add CODEOWNERS, remove MAINTAINERS.md

Documentation:

• Rewrite README.md to standard template structure (CICS TS V5.5, Java SE 8, Servlet 3.1, build badge with branch param)