Add Java and Spring Boot presets with API-driven actions

[fbrissi]

Add Java and Spring Boot project presets, database/cache recipes, and API/input automation actions so Java projects can be initialized and configured through Kool presets.

Java project setup

• Add Java with Gradle and Spring Boot preset definitions
• Document the new Java presets

Java services and recipes

• Add Java database and cache recipes
• Add PostgreSQL 16 template support

Automation actions

• Support input actions and environment references
• Support API-backed single and multi-select prompts

Validation

• Verify core Go tests pass
• Confirm compatibility with dependent docker-java PR feat: add modern Java images docker-java#69