♻️ (html): Añade valores extra a Props

- Reordena campos, variantes y métodos para mayor consistencia interna.
- Añade `extra_or`, `extra_or_default` y `extra_or_else` a `Props`.
- Mejora la documentación y amplía los tests de integración.

tests/html_props_classes.rs

@@ -0,0 +1,231 @@
+use pagetop::prelude::*;
+
+fn assert_classes(p: &Props, expected: Option<&str>) {
+    let got = p.get_classes();
+    assert_eq!(
+        got.as_deref(),
+        expected,
+        "Expected {:?}, got {:?}",
+        expected,
+        got
+    );
+}
+
+// **< Props::classes (construction) >**************************************************************
+
+#[pagetop::test]
+async fn classes_new_empty_and_whitespace_is_empty() {
+    assert_classes(&Props::classes(""), None);
+    assert_classes(&Props::classes("   "), None);
+    assert_classes(&Props::classes("\t\n\r  "), None);
+}
+
+#[pagetop::test]
+async fn classes_new_normalizes_and_dedups_and_preserves_first_occurrence_order() {
+    let p = Props::classes("Btn btn BTN  btn-primary  BTN-PRIMARY");
+    assert_classes(&p, Some("btn btn-primary"));
+    assert!(p.has_class("BTN"));
+    assert!(p.has_class("btn-primary"));
+}
+
+// **< PropsOp::add_classes >***********************************************************************
+
+#[pagetop::test]
+async fn classes_add_appends_unique_and_normalizes() {
+    let p = Props::classes("a b").with_prop(PropsOp::add_classes("C b  D"));
+    assert_classes(&p, Some("a b c d"));
+}
+
+#[pagetop::test]
+async fn classes_add_ignores_empty_input() {
+    let p = Props::classes("a b").with_prop(PropsOp::add_classes("   \t"));
+    assert_classes(&p, Some("a b"));
+}
+
+#[pagetop::test]
+async fn classes_add_same_tokens_is_noop() {
+    let p = Props::classes("a b").with_prop(PropsOp::add_classes("A B a b"));
+    assert_classes(&p, Some("a b"));
+}
+
+#[pagetop::test]
+async fn classes_add_rejects_non_ascii_is_noop() {
+    let p = Props::classes("a b").with_prop(PropsOp::add_classes("c ñ d"));
+    assert_classes(&p, Some("a b"));
+}
+
+// **< PropsOp::prepend_classes >*******************************************************************
+
+#[pagetop::test]
+async fn classes_prepend_inserts_at_front_preserving_new_order() {
+    let p = Props::classes("c d").with_prop(PropsOp::prepend_classes("A b"));
+    assert_classes(&p, Some("a b c d"));
+}
+
+#[pagetop::test]
+async fn classes_prepend_inserts_new_tokens_skipping_duplicates() {
+    let p = Props::classes("b c").with_prop(PropsOp::prepend_classes("a b d"));
+    assert_classes(&p, Some("a d b c"));
+}
+
+#[pagetop::test]
+async fn classes_prepend_ignores_empty_input() {
+    let p = Props::classes("a b").with_prop(PropsOp::prepend_classes(""));
+    assert_classes(&p, Some("a b"));
+}
+
+// **< PropsOp::set / remove ("class") >************************************************************
+
+#[pagetop::test]
+async fn classes_reset_replaces_entire_list_and_dedups() {
+    let p = Props::classes("a b c").with_prop(PropsOp::set("class", "X  y  y  Z"));
+    assert_classes(&p, Some("x y z"));
+}
+
+#[pagetop::test]
+async fn classes_reset_with_empty_input_clears() {
+    let p = Props::classes("a b").with_prop(PropsOp::set("class", " \n "));
+    assert_classes(&p, None);
+}
+
+#[pagetop::test]
+async fn classes_reset_with_non_ascii_is_noop() {
+    let p = Props::classes("a b").with_prop(PropsOp::set("class", "ñ"));
+    assert_classes(&p, Some("a b"));
+}
+
+#[pagetop::test]
+async fn classes_remove_attr_clears_all_classes() {
+    let p = Props::classes("btn primary").with_prop(PropsOp::remove("class"));
+    assert_classes(&p, None);
+}
+
+// **< PropsOp::remove_classes >********************************************************************
+
+#[pagetop::test]
+async fn classes_remove_is_case_insensitive() {
+    let p = Props::classes("a b c d").with_prop(PropsOp::remove_classes("B  D"));
+    assert_classes(&p, Some("a c"));
+}
+
+#[pagetop::test]
+async fn classes_remove_non_existing_is_noop() {
+    let p = Props::classes("a b c").with_prop(PropsOp::remove_classes("x y z"));
+    assert_classes(&p, Some("a b c"));
+}
+
+#[pagetop::test]
+async fn classes_remove_with_extra_whitespace() {
+    let p = Props::classes("a b c d").with_prop(PropsOp::remove_classes("   b\t\t  \n d  "));
+    assert_classes(&p, Some("a c"));
+}
+
+// **< has_class / has_any_class >******************************************************************
+
+#[pagetop::test]
+async fn classes_contains_single() {
+    let p = Props::classes("btn btn-primary");
+    assert!(p.has_class("btn"));
+    assert!(p.has_class("BTN"));
+    assert!(!p.has_class("missing"));
+}
+
+#[pagetop::test]
+async fn classes_contains_all_and_any() {
+    let p = Props::classes("btn btn-primary active");
+    assert!(p.has_class("btn active"));
+    assert!(p.has_class("BTN BTN-PRIMARY"));
+    assert!(!p.has_class("btn missing"));
+    assert!(p.has_any_class("missing active"));
+    assert!(p.has_any_class("BTN-PRIMARY missing"));
+    assert!(!p.has_any_class("missing other"));
+}
+
+#[pagetop::test]
+async fn classes_contains_empty_and_whitespace_is_false() {
+    let p = Props::classes("a b");
+    assert!(!p.has_class(""));
+    assert!(!p.has_class("   \t"));
+    assert!(!p.has_any_class(""));
+    assert!(!p.has_any_class(" \n "));
+}
+
+#[pagetop::test]
+async fn classes_contains_non_ascii_is_false() {
+    let p = Props::classes("a b");
+    assert!(!p.has_class("ñ"));
+    assert!(!p.has_any_class("a ñ"));
+}
+
+// **< is_classes_empty >***************************************************************************
+
+#[pagetop::test]
+async fn props_is_classes_empty_on_default() {
+    assert!(Props::default().is_classes_empty());
+}
+
+#[pagetop::test]
+async fn props_is_classes_empty_false_after_add_classes() {
+    assert!(!Props::classes("btn").is_classes_empty());
+}
+
+#[pagetop::test]
+async fn props_is_classes_empty_true_after_remove_class() {
+    let p = Props::classes("btn").with_prop(PropsOp::remove("class"));
+    assert!(p.is_classes_empty());
+}
+
+// **< get_classes / get_prop("class") >************************************************************
+
+#[pagetop::test]
+async fn classes_get_returns_none_when_empty_some_when_not() {
+    assert_classes(&Props::classes(" "), None);
+    assert_classes(&Props::classes("a"), Some("a"));
+}
+
+#[pagetop::test]
+async fn get_prop_class_returns_joined_classes() {
+    let p = Props::classes("btn btn-primary").with_prop(PropsOp::add_classes("active"));
+    assert_eq!(
+        p.get_prop("class"),
+        Some("btn btn-primary active".to_string())
+    );
+}
+
+#[pagetop::test]
+async fn get_prop_class_matches_get_classes() {
+    let p = Props::classes("btn active");
+    assert_eq!(p.get_prop("class"), p.get_classes());
+}
+
+// **< HTML rendering >*****************************************************************************
+
+#[pagetop::test]
+async fn props_classes_renders_class_attribute() {
+    let p = Props::classes("btn btn-primary");
+    assert_eq!(
+        html! { button (p) { "OK" } }.into_string(),
+        r#"<button class="btn btn-primary">OK</button>"#
+    );
+}
+
+#[pagetop::test]
+async fn props_classes_can_be_extended_with_add_classes() {
+    let p = Props::classes("btn").with_prop(PropsOp::add_classes("active"));
+    assert_eq!(
+        html! { button (p) { "OK" } }.into_string(),
+        r#"<button class="btn active">OK</button>"#
+    );
+}
+
+// **< Combined sequences >*************************************************************************
+
+#[pagetop::test]
+async fn classes_order_is_stable_for_existing_items() {
+    let p = Props::classes("a b c")
+        .with_prop(PropsOp::add_classes("d")) // a b c d
+        .with_prop(PropsOp::prepend_classes("x")) // x a b c d
+        .with_prop(PropsOp::remove_classes("b")) // x a c d
+        .with_prop(PropsOp::add_classes("b")); // x a c d b
+    assert_classes(&p, Some("x a c d b"));
+}