feat(game): Quest model, QuestLog, START_QUEST effect

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

Semesterprojekt/src/main/java/thb/jeanluc/adventure/game/Effects.java

@@ -27,6 +27,7 @@ public final class Effects {
             }
             case REMOVE_ITEM -> ctx.getPlayer().removeItem(e.arg());
             case SAY -> ctx.getIo().write(e.arg());
+            case START_QUEST -> ctx.getQuestLog().start(e.arg());
         }
     }
 

Semesterprojekt/src/main/java/thb/jeanluc/adventure/game/GameContext.java

@@ -26,4 +26,7 @@ public class GameContext {
 
     /** Mutable world flags. Created fresh per context; not a constructor arg. */
     private final GameState state = new GameState();
+
+    /** Runtime quest progress. Created fresh per context; not a constructor arg. */
+    private final QuestLog questLog = new QuestLog();
 }

Semesterprojekt/src/main/java/thb/jeanluc/adventure/game/QuestLog.java

@@ -0,0 +1,49 @@
+package thb.jeanluc.adventure.game;
+
+import java.util.Collections;
+import java.util.LinkedHashMap;
+import java.util.LinkedHashSet;
+import java.util.Map;
+import java.util.Set;
+
+/** Runtime quest progress: current stage per active quest, plus completed ids. */
+public class QuestLog {
+
+    private final Map<String, Integer> stageIndex = new LinkedHashMap<>();
+    private final Set<String> completed = new LinkedHashSet<>();
+
+    public void start(String id) {
+        if (!completed.contains(id)) {
+            stageIndex.putIfAbsent(id, 0);
+        }
+    }
+
+    public boolean isActive(String id) {
+        return stageIndex.containsKey(id);
+    }
+
+    public boolean isCompleted(String id) {
+        return completed.contains(id);
+    }
+
+    public int stageIndex(String id) {
+        return stageIndex.getOrDefault(id, 0);
+    }
+
+    public void advance(String id) {
+        stageIndex.merge(id, 1, Integer::sum);
+    }
+
+    public void complete(String id) {
+        stageIndex.remove(id);
+        completed.add(id);
+    }
+
+    public Set<String> active() {
+        return Collections.unmodifiableSet(stageIndex.keySet());
+    }
+
+    public Set<String> completed() {
+        return Collections.unmodifiableSet(completed);
+    }
+}