semesterprojekt: finalize 1.0 deliverable (run profiles, dungeon room, README)

- pom.xml: exec-maven-plugin run profiles (@run console, @gui Swing)
- rooms.yaml: add dungeon room reachable south of the kitchen
- README.md: project overview, build/run/play instructions
- .gitignore: ignore brainstorming companion dir (.superpowers/)

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

Semesterprojekt/.gitignore

@@ -36,4 +36,4 @@ build/
 .vscode/
 
 ### Mac OS ###
-.DS_Store
+.DS_Store.superpowers/