Add extension skills, server instructions, and CLAUDE.md generation

[phillip-kruger]

Summary

Adds extension skill support, MCP server instructions, project-level CLAUDE.md generation, and a quarkus/update tool to improve how AI coding agents work with Quarkus projects.

Extension Skills (SkillReader)

• Reads extension skills from the new aggregated quarkus-extension-skills JAR (one JAR per Quarkus version containing all composed SKILL.md files)
• Auto-downloads the JAR from Maven repos if not in local .m2
• Respects Maven mirror configuration from:
  • .mvn/maven.config (project-level custom settings file via -s)
  • ~/.m2/settings.xml (user-level mirrors)
  • ${MAVEN_HOME}/conf/settings.xml (global mirrors)
• Handles mirrorOf patterns: central, *, external:*, comma-separated, !central exclusions
• Skips download for SNAPSHOT versions (not on release repos)

Update Tool (quarkus/update)

New tool that checks if a Quarkus project is up-to-date and provides a unified upgrade report:

• Detects build tool (Maven, Gradle, Gradle Kotlin DSL) and current Quarkus version
• Fetches the latest available version from code-with-quarkus-compare tags
• Compares build files against reference projects, highlighting meaningful differences
• Runs quarkus update --dry-run (if CLI is available) to preview automated migrations and patches
• Provides a link to the full structural diff between versions
• Returns a unified report with recommended actions

Based on the quarkus-update skill.

MCP Server Instructions

Configures quarkus.mcp.server.server-info.instructions to direct AI agents to:

• Use quarkus/update (via subagent) when starting work on existing projects
• Use quarkus/skills before writing any code (extension-specific patterns and pitfalls)
• Use quarkus/searchDocs over generic documentation tools (Context7, web search)
• Use quarkus/callTool for testing via subagents
• Follow the correct workflow: update → start → skills → docs → code → test

CLAUDE.md Generation

quarkus/create now generates a CLAUDE.md in every new project with:

• Required workflow (update → skills → docs → searchTools → callTool)
• Rules (extension-first, always test, keep README updated)
• Testing instructions using subagents for non-blocking test execution

Other Improvements

• Shortened tool descriptions for better readability
• Auto-enables Dev MCP (-Dquarkus.dev-mcp.enabled=true) when starting apps
• Updated dependency versions

Depends on (Quarkus core PRs)

• quarkusio/quarkus#53195 — aggregate-skills mechanism
• quarkusio/quarkus#53196 — extension skill files
• quarkusio/quarkus#53182 — one-shot testing tools