Add Github Copilot modernization for java plugin (#1523)

* sync: java-upgrade plugin update from devdiv-azure-service-dmitryr/azure-java-migration-copilot-vscode-extension@187b2f8

Source commit: 187b2f85130550fbb5213b55347ab4afbb8c17e1

Source branch: xiading/sync-java-2

Triggered by: xiading_microsoft

Workflow: https://github.com/devdiv-azure-service-dmitryr/azure-java-migration-copilot-vscode-extension/actions/runs/24984055440

* Fix modernize-java plugin checklist issues

- Fix keyword casing: 'Java' → 'java' in plugin.json
- Add plugins/modernize-java/README.md based on upstream microsoft/modernize-java
- Remove hook declarations referencing missing scripts (recordToolUse.sh/.ps1)
- Run npm run build to update docs/README.plugins.md, docs/README.agents.md, and marketplace.json

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

* Fix README install command to use awesome-copilot marketplace

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

---------

Co-authored-by: github-actions[bot] <github-actions[bot]@users.noreply.github.com>
Co-authored-by: app_modernization <app_modernization@example.com>
Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

docs/README.plugins.md

@@ -51,6 +51,7 @@ See [CONTRIBUTING.md](../CONTRIBUTING.md#adding-plugins) for guidelines on how t
 | [java-mcp-development](../plugins/java-mcp-development/README.md) | Complete toolkit for building Model Context Protocol servers in Java using the official MCP Java SDK with reactive streams and Spring Boot integration. | 2 items | java, mcp, model-context-protocol, server-development, sdk, reactive-streams, spring-boot, reactor |
 | [kotlin-mcp-development](../plugins/kotlin-mcp-development/README.md) | Complete toolkit for building Model Context Protocol (MCP) servers in Kotlin using the official io.modelcontextprotocol:kotlin-sdk library. Includes instructions for best practices, a prompt for generating servers, and an expert chat mode for guidance. | 2 items | kotlin, mcp, model-context-protocol, kotlin-multiplatform, server-development, ktor |
 | [mcp-m365-copilot](../plugins/mcp-m365-copilot/README.md) | Comprehensive collection for building declarative agents with Model Context Protocol integration for Microsoft 365 Copilot | 4 items | mcp, m365-copilot, declarative-agents, api-plugins, model-context-protocol, adaptive-cards |
+| [modernize-java](../plugins/modernize-java/README.md) | AI-powered Java modernization and upgrade assistant. Helps upgrade Java and Spring Boot applications to the latest versions. | 1 items | java, modernization, upgrade, migration, spring-boot |
 | [napkin](../plugins/napkin/README.md) | Visual whiteboard collaboration for Copilot CLI. Opens an interactive whiteboard in your browser where you can draw, sketch, and add sticky notes — then share everything back with Copilot. Copilot sees your drawings and responds with analysis, suggestions, and ideas. | 1 items | whiteboard, visual, collaboration, brainstorming, non-technical, drawing, sticky-notes, accessibility, copilot-cli, ux |
 | [noob-mode](../plugins/noob-mode/README.md) | Plain-English translation layer for non-technical Copilot CLI users. Translates every approval prompt, error message, and technical output into clear, jargon-free English with color-coded risk indicators. | 1 items | accessibility, plain-english, non-technical, beginner, translation, copilot-cli, ux |
 | [openapi-to-application-csharp-dotnet](../plugins/openapi-to-application-csharp-dotnet/README.md) | Generate production-ready .NET applications from OpenAPI specifications. Includes ASP.NET Core project scaffolding, controller generation, entity framework integration, and C# best practices. | 2 items | openapi, code-generation, api, csharp, dotnet, aspnet |