fix(html): isolate shared nodes in Each

Co-Authored-By: Virgil <virgil@lethean.io>

node.go

@@ -909,7 +909,7 @@ func (n *eachNode[T]) setAttr(key, value string) {
 
 	prev := n.fn
 	n.fn = func(item T) Node {
-		return Attr(prev(item), key, value)
+		return Attr(cloneNode(prev(item)), key, value)
 	}
 }
 

node_test.go

@@ -1112,6 +1112,22 @@ func TestAttr_ThroughEachNode(t *testing.T) {
 	}
 }
 
+func TestAttr_ThroughEachNode_IsolatedFromSharedItems(t *testing.T) {
+	ctx := NewContext()
+	shared := El("span", Raw("item"))
+	node := Each([]int{1, 2}, func(int) Node {
+		return shared
+	})
+
+	Attr(node, "class", "shared")
+
+	got := node.Render(ctx)
+	want := `<span class="shared">item</span><span class="shared">item</span>`
+	if got != want {
+		t.Errorf("Attr through Each should clone shared items, got %q, want %q", got, want)
+	}
+}
+
 func TestAttr_ThroughEachSeqNode(t *testing.T) {
 	ctx := NewContext()
 	node := EachSeq(slices.Values([]string{"a", "b"}), func(item string) Node {