Migrate backend from Go to Quarkus (Java 21 / JAX-RS)

- Replaced Go stdlib server with Quarkus (RESTEasy Reactive + Jackson)
- 7 Java classes: Game POJO, GameService (JSON file I/O), 4 REST resources, static file serving
- Same JSON-per-game storage, same ZIP upload + bundle creation
- Same Svelte frontend (unchanged), built into the JAR via maven-resources-plugin
- Multi-stage Dockerfile: Node → Maven → JRE runtime

.gitignore

@@ -1,8 +1,17 @@
 # Dependencies
 node_modules/
-frontend/dist/
 frontend/node_modules/
 
+# Built output
+frontend/dist/
+dist/
+
+# Maven / Java
+target/
+*.class
+*.jar
+*.war
+
 # Runtime data
 data/games/*
 data/artwork/*
@@ -11,8 +20,12 @@ data/saves/*
 !data/artwork/.gitkeep
 !data/saves/.gitkeep
 
-# Binary
-dostalgia
+# IDE
+.vscode/
+.idea/
+*.iml
+*.ipr
+*.iws
 
 # Test/upload artifacts
 *.zip
@@ -20,6 +33,6 @@ dostalgia
 *.jsdos
 *.JSDOS
 
-# IDE
-.vscode/
-.idea/
+# OS
+.DS_Store
+Thumbs.db