Enhance project setup and configuration for RolePlay application

- Update .gitignore to include additional build outputs and IDE files.
- Modify pom.xml to add new plugin versions and configurations for frontend and OpenAPI TypeScript client generation.
- Introduce project guidelines in roleplay-project.mdc, detailing architecture, coding standards, and testing practices.
- Add initial documentation for the RolePlay concept and specifications.
- Implement catch-all JAX-RS resource for serving the React application and establish API base path in application.yml.
- Create foundational web components and TypeScript configuration for the frontend application.

.gitignore

@@ -1,2 +1,21 @@
+# Maven build output
 /target/
+
+# Vite build output (written into resources so it gets into the JAR)
+src/main/resources/META-INF/resources/
+
+# IDE
 /.idea/
+*.iml
+
+# Node dependencies
+node_modules/
+
+# OpenAPI-generated TypeScript client (regenerated by mvn generate-sources)
+src/main/web/src/api/generated/
+
+# TypeScript incremental build cache
+*.tsbuildinfo
+
+# OS metadata
+.DS_Store