feat(io): AsciiMap console renderer for MapView

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

Semesterprojekt/src/test/java/thb/jeanluc/adventure/io/text/AsciiMapTest.java

@@ -0,0 +1,36 @@
+package thb.jeanluc.adventure.io.text;
+
+import org.junit.jupiter.api.Test;
+import java.util.List;
+import static org.assertj.core.api.Assertions.assertThat;
+
+class AsciiMapTest {
+
+    @Test
+    void rendersVisitedNameCurrentAndKnownStub() {
+        RoomCell kitchen = new RoomCell("kitchen", "Kitchen", 0, 1, CellState.CURRENT);
+        RoomCell hallway = new RoomCell("hallway", "Hallway", 0, 0, CellState.VISITED);
+        RoomCell cellar = new RoomCell("cellar", "?", 1, 1, CellState.KNOWN);
+        MapView v = new MapView(List.of(kitchen, hallway, cellar),
+                List.of(new Connection(hallway, kitchen), new Connection(kitchen, cellar)));
+
+        String out = AsciiMap.render(v, true).plainText();
+
+        assertThat(out).contains("Kitchen");
+        assertThat(out).contains("Hallway");
+        assertThat(out).contains("?");
+    }
+
+    @Test
+    void emptyMapRendersPlaceholder() {
+        String out = AsciiMap.render(new MapView(List.of(), List.of()), true).plainText();
+        assertThat(out).containsIgnoringCase("no map");
+    }
+
+    @Test
+    void asciiModeUsesPlusFrames() {
+        RoomCell only = new RoomCell("kitchen", "Kitchen", 0, 0, CellState.CURRENT);
+        String out = AsciiMap.render(new MapView(List.of(only), List.of()), false).plainText();
+        assertThat(out).contains("+").doesNotContain("┌");
+    }
+}