docs: add greenfield Spring Boot pirate-speak preset demo to README (#1878)

Author: mnriem

README.md

@@ -160,6 +160,8 @@ See Spec-Driven Development in action across different scenarios with these comm
 
 - **[Brownfield Go / React dashboard demo](https://github.com/mnriem/spec-kit-go-brownfield-demo)** — Demonstrates spec-kit driven entirely from the **terminal using GitHub Copilot CLI**. Extends NASA's open-source Hermes ground support system (Go) with a lightweight React-based web telemetry dashboard, showing that the full constitution → specify → plan → tasks → implement workflow works from the terminal.
 
+- **[Greenfield Spring Boot MVC with a custom preset](https://github.com/mnriem/spec-kit-pirate-speak-preset-demo)** — Builds a Spring Boot MVC application from scratch using a custom pirate-speak preset, demonstrating how presets can reshape the entire spec-kit experience: specifications become "Voyage Manifests," plans become "Battle Plans," and tasks become "Crew Assignments" — all generated in full pirate vernacular without changing any tooling.
+
 ## 🤖 Supported AI Agents
 
 | Agent                                                                                | Support | Notes                                                                                                                                     |