feat(html): add id and for helpers

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

docs/architecture.md

@@ -56,6 +56,8 @@ Accessibility-oriented helpers are also provided for common attribute patterns:
 - `AriaRequired(node, required)`
 - `TabIndex(node, index)`
 - `AutoFocus(node)`
+- `ID(node, id)`
+- `For(node, target)`
 
 ### Safety Guarantees
 

node.go

@@ -395,6 +395,18 @@ func AutoFocus(n Node) Node {
 	return Attr(n, "autofocus", "autofocus")
 }
 
+// node.go: ID sets the id attribute on an element node.
+// Example: ID(El("section"), "main-content").
+func ID(n Node, id string) Node {
+	return Attr(n, "id", id)
+}
+
+// node.go: For sets the for attribute on an element node.
+// Example: For(El("label"), "email-input").
+func For(n Node, target string) Node {
+	return Attr(n, "for", target)
+}
+
 func joinNonEmpty(parts ...string) string {
 	if len(parts) == 0 {
 		return ""

node_test.go

@@ -492,6 +492,26 @@ func TestClassHelper_IgnoresWhitespaceClasses(t *testing.T) {
 	}
 }
 
+func TestIDHelper(t *testing.T) {
+	ctx := NewContext()
+	node := ID(El("section", Raw("content")), "main-content")
+	got := node.Render(ctx)
+	want := `<section id="main-content">content</section>`
+	if got != want {
+		t.Errorf("ID() = %q, want %q", got, want)
+	}
+}
+
+func TestForHelper(t *testing.T) {
+	ctx := NewContext()
+	node := For(El("label", Raw("Email")), "email-input")
+	got := node.Render(ctx)
+	want := `<label for="email-input">Email</label>`
+	if got != want {
+		t.Errorf("For() = %q, want %q", got, want)
+	}
+}
+
 func TestAriaHiddenHelper(t *testing.T) {
 	ctx := NewContext()