Update Java modernization documentation for CLI plugin

This pull request updates documentation for modernizing Java applications using the GitHub Copilot modernization plugin in the Copilot CLI and related tools. The changes improve clarity, update instructions to reflect the latest plugin-based workflow, add support for OpenJDK 25, and provide new guidance for enterprise policy integration. **Major documentation improvements and feature updates:** ### Copilot CLI modernization documentation overhaul - Completely rewrote the `github-copilot-app-modernization-for-java-copilot-cli.md` article to focus on the new plugin-based workflow, including detailed installation, agent selection, and usage instructions for modernization tasks. Added a comprehensive explanation of the three-phase workflow (assessment, planning, execution), troubleshooting steps, and guidance for defining enterprise rulebooks to enforce modernization policies. [[1]](diffhunk://#diff-def5c6d220764054f1c404b90f32c93928bbf8f224b6fd95da5bf1f16eebb62eL4-R9) [[2]](diffhunk://#diff-def5c6d220764054f1c404b90f32c93928bbf8f224b6fd95da5bf1f16eebb62eL18-R18) [[3]](diffhunk://#diff-def5c6d220764054f1c404b90f32c93928bbf8f224b6fd95da5bf1f16eebb62eL27-R166) [[4]](diffhunk://#diff-def5c6d220764054f1c404b90f32c93928bbf8f224b6fd95da5bf1f16eebb62eL117-R186) [[5]](diffhunk://#diff-def5c6d220764054f1c404b90f32c93928bbf8f224b6fd95da5bf1f16eebb62eL133-R206) [[6]](diffhunk://#diff-def5c6d220764054f1c404b90f32c93928bbf8f224b6fd95da5bf1f16eebb62eR217-L154) ### OpenJDK 25 support - Added OpenJDK 25 as a supported target in assessment and modernization configuration examples for both Visual Studio Code and IntelliJ IDEA, including updates to value tables and YAML configuration samples. [[1]](diffhunk://#diff-dd634dcc68e38c7fff6b36b74fe6704703693d981686ab779df6038fd9bfd54dR34) [[2]](diffhunk://#diff-dd634dcc68e38c7fff6b36b74fe6704703693d981686ab779df6038fd9bfd54dL76-R82) [[3]](diffhunk://#diff-9041196ca257b5355f134168672c38b318a675a9a8dc7a084a095be26e20e522L73-R74) [[4]](diffhunk://#diff-9041196ca257b5355f134168672c38b318a675a9a8dc7a084a095be26e20e522L123-R128) ### Prerequisite and version updates - Updated Visual Studio Code minimum version requirement from 1.106 to 1.113 in all relevant prerequisites and quickstart includes. [[1]](diffhunk://#diff-97060eb8307ace3e9480768a585cfe3785736de21c9eebf8b5f1d1b20f47d979L7-R7) [[2]](diffhunk://#diff-6016b5c60d421efd274fc17006ec6a052d6f030d287aa7ca591f72b6728561cdL10-R10) ### Minor improvements and terminology updates - Clarified references to the modernization agent (now called "modernize agent") and updated quickstart navigation links for consistency.…sion requirements and agent naming