✨ (htmx): Añade soporte HTMX a tablas ordenables

- Nuevo `SortDir` en `pagetop::html` para representar direcciones de
  orden (asc/desc) y calcular la siguiente al pulsar una cabecera.
- `hx_table::sort_link()` construye el enlace de ordenación con los
  cuatro atributos `hx-*` fijos, reutilizable en cualquier tabla.
- `HtmxResponse` usa `RoutePath` en `location`/`push_url`/`replace_url`/
  `redirect` para preservar "lang"; `location_json()` se separa de
  `location()` para el caso de configuración JSON personalizada.
- Añade el módulo `prelude` y una batería de tests para hx, hx_table,
  request, response y extension.

extensions/pagetop-htmx/tests/hx_table.rs

@@ -0,0 +1,162 @@
+use pagetop::prelude::*;
+use pagetop_htmx::prelude::*;
+
+// Forces an effective language different from the default negotiated one (en-US, with no `?lang` in
+// the request), so that `Context::route()` decides to propagate `?lang=...` in local routes.
+fn cx_with_lang(lang: &str) -> Context {
+    Context::new(None).with_langid(&Locale::resolve(lang))
+}
+
+async fn render_column(column: table::Column) -> String {
+    let mut table = Table::new().with_column(column);
+    table.render(&mut Context::default()).await.into_string()
+}
+
+// **< sort_link() - htmx attributes >**************************************************************
+
+#[pagetop::test]
+async fn sort_link_sets_the_four_fixed_htmx_attributes() {
+    let column = table::Column::new(L10n::n("User")).with_sort(hx_table::sort_link(
+        "/admin/users",
+        "#user-table",
+        None,
+    ));
+
+    let html = render_column(column).await;
+
+    assert!(html.contains(r#"hx-get="/admin/users""#));
+    assert!(html.contains(r##"hx-target="#user-table""##));
+    assert!(html.contains(r#"hx-swap="outerHTML""#));
+    assert!(html.contains(r#"hx-push-url="true""#));
+}
+
+#[pagetop::test]
+async fn sort_link_href_matches_the_hx_get_value() {
+    // The link must work with or without HTMX: `href` is the real destination, and `hx-get` must
+    // request that very same URL so both navigation paths land on the same state.
+    let column = table::Column::new(L10n::n("User")).with_sort(hx_table::sort_link(
+        "/admin/users?sort=username",
+        "#user-table",
+        None,
+    ));
+
+    let html = render_column(column).await;
+
+    assert!(html.contains(r#"href="/admin/users?sort=username""#));
+    assert!(html.contains(r#"hx-get="/admin/users?sort=username""#));
+}
+
+#[pagetop::test]
+async fn sort_link_target_is_configurable_per_table() {
+    let column = table::Column::new(L10n::n("Email")).with_sort(hx_table::sort_link(
+        "/admin/users",
+        "#other-wrapper",
+        None,
+    ));
+
+    let html = render_column(column).await;
+
+    assert!(html.contains(r##"hx-target="#other-wrapper""##));
+}
+
+// **< sort_link() - sort direction propagation >***************************************************
+
+#[pagetop::test]
+async fn sort_link_without_active_direction_marks_aria_sort_none() {
+    let column = table::Column::new(L10n::n("User")).with_sort(hx_table::sort_link(
+        "/admin/users",
+        "#user-table",
+        None,
+    ));
+
+    let html = render_column(column).await;
+
+    assert!(html.contains(r#"aria-sort="none""#));
+}
+
+#[pagetop::test]
+async fn sort_link_with_active_direction_marks_aria_sort_and_css_class() {
+    let column = table::Column::new(L10n::n("User")).with_sort(hx_table::sort_link(
+        "/admin/users",
+        "#user-table",
+        SortDir::Desc,
+    ));
+
+    let html = render_column(column).await;
+
+    assert!(html.contains(r#"aria-sort="descending""#));
+    assert!(html.contains("table-sort table-sort-desc"));
+}
+
+// **< sort_link() - RoutePath / Context::route() integration >*************************************
+
+#[pagetop::test]
+async fn sort_link_with_a_bare_literal_href_never_adds_lang() {
+    // `sort_link()` does not receive `cx`, so it cannot add `lang` on its own: passing a raw
+    // literal must leave both `href` and `hx-get` exactly as given.
+    let column = table::Column::new(L10n::n("User")).with_sort(hx_table::sort_link(
+        "/admin/users",
+        "#user-table",
+        None,
+    ));
+
+    let html = render_column(column).await;
+
+    assert!(html.contains(r#"href="/admin/users""#));
+    assert!(!html.contains("lang="));
+}
+
+#[pagetop::test]
+async fn sort_link_carries_through_a_lang_aware_href_unchanged() {
+    // The caller is expected to resolve `href` with `cx.route(...)` beforehand (see the type's own
+    // doc example); `sort_link()` must not re-encode or otherwise alter what it receives.
+    let cx = cx_with_lang("es-ES");
+    let href = cx.route("/admin/users");
+
+    let column = table::Column::new(L10n::n("User")).with_sort(hx_table::sort_link(
+        href,
+        "#user-table",
+        None,
+    ));
+
+    let html = render_column(column).await;
+
+    assert!(html.contains(r#"href="/admin/users?lang=es-ES""#));
+    assert!(html.contains(r#"hx-get="/admin/users?lang=es-ES""#));
+}
+
+#[pagetop::test]
+async fn sort_link_carries_through_extra_query_params_in_order() {
+    let cx = cx_with_lang("es-ES");
+    let href = cx
+        .route("/admin/users")
+        .with_param("sort", "username")
+        .with_param("dir", "desc");
+
+    let column = table::Column::new(L10n::n("User")).with_sort(hx_table::sort_link(
+        href,
+        "#user-table",
+        SortDir::Desc,
+    ));
+
+    let html = render_column(column).await;
+
+    // `&` is escaped to `&amp;` because this ends up inside an HTML attribute value.
+    assert!(html.contains(r#"href="/admin/users?lang=es-ES&amp;sort=username&amp;dir=desc""#));
+}
+
+#[pagetop::test]
+async fn sort_link_with_an_external_href_is_left_untouched() {
+    // `Context::route()` never adds `lang` to a URL that looks external; `sort_link()` must not
+    // reintroduce it either, since it only forwards whatever `RoutePath` it receives.
+    let cx = cx_with_lang("es-ES");
+    let href = cx.route("https://example.com/export");
+
+    let column =
+        table::Column::new(L10n::n("Export")).with_sort(hx_table::sort_link(href, "#table", None));
+
+    let html = render_column(column).await;
+
+    assert!(html.contains(r#"href="https://example.com/export""#));
+    assert!(!html.contains("lang="));
+}