fix(html): fix hashCode for triangle

The bug caused HTML class and CSS selector to have different IDs, breaking triangle rendering.

src/test/java/ovh/gasser/newshapes/util/StreamableTest.java

@@ -0,0 +1,48 @@
+package ovh.gasser.newshapes.util;
+
+import org.junit.jupiter.api.Test;
+
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.List;
+import java.util.stream.Stream;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+class StreamableTest {
+
+    private static class TestStreamable implements Streamable<String> {
+        private final List<String> elements;
+
+        TestStreamable(List<String> elements) {
+            this.elements = new ArrayList<>(elements);
+        }
+
+        @Override
+        public java.util.Iterator<String> iterator() {
+            return elements.iterator();
+        }
+    }
+
+    @Test
+    void testStreamReturnsStreamOfElements() {
+        List<String> testData = Arrays.asList("a", "b", "c");
+        Streamable<String> streamable = new TestStreamable(testData);
+
+        Stream<String> result = streamable.stream();
+
+        assertNotNull(result);
+        assertEquals(testData, result.toList());
+    }
+
+    @Test
+    void testStreamEmptyCollection() {
+        List<String> emptyData = new ArrayList<>();
+        Streamable<String> streamable = new TestStreamable(emptyData);
+
+        Stream<String> result = streamable.stream();
+
+        assertNotNull(result);
+        assertTrue(result.toList().isEmpty());
+    }
+}