Document getting started and minimal archetype

[diegosilval]

Implements Website Phase 3 for Eclipse Coffee Builder.

Changes include:

• add a practical Getting Started guide for the current development snapshot
• document Java, Maven, and Git prerequisites
• document the local reactor installation workflow
• document the Jakarta EE Minimal Archetype
• distinguish accepted archetype inputs from automated test coverage
• document Jakarta EE 10 and Jakarta EE 11 Java release behavior
• add verified Jakarta EE 11 and Jakarta EE 10 generation examples
• document generated project structure and artifactId/package sanitization
• add navigation between Getting Started, the archetype, and Maven Plugin documentation

Validation:

• complete Maven reactor install succeeds
• plugin: 149 tests pass
• all four archetype integration scenarios pass
• documented Jakarta EE 11 project generates and builds successfully
• documented Jakarta EE 10 project generates and builds successfully
• Hugo production and subpath builds pass with --panicOnWarning
• route, cross-link, prohibited-content, and UTF-8 checks pass

The documented 0.1.0-SNAPSHOT version is explicitly identified as a locally installed development snapshot, not a published stable release.