Slice 10 b2: UiSurface list/container data bindings

The stage dock is one RML document rendering a variable list of slots (one per
minimized window). Adds the deferred slice-6 list-binding shape to UiSurface:
bind_list(name, count) + typed per-row fields bind_list_string/int/double/bool
(list, field, getter(row)) read as {{ row.field }} via data-for, and
bind_list_event(list, event, callback(row)) routed from data-event-*(it_index).
dirty(<list>) re-reads count + visible rows. Same error-isolation + bind-before-
first-frame contract as the scalar bindings; nested lists unsupported.

kernel suite green on build + build-asan (asan clean). Edits confined to packages/kernel/.

1 files changed, 8 insertions, 0 deletions

diff --git a/packages/kernel/src/server.cpp b/packages/kernel/src/server.cpp
index b302c68..95631df 100644
--- a/packages/kernel/src/server.cpp
+++ b/packages/kernel/src/server.cpp
@@ -89,6 +89,14 @@ auto Server::ui_pixel(int x, int y) const -> unsigned int {
     return impl_->substrate != nullptr ? impl_->substrate->surface_pixel(x, y) : 0U;
 }
 
+auto Server::ui_element_count(const char* tag) const -> int {
+    return impl_->substrate != nullptr ? impl_->substrate->element_count(tag) : 0;
+}
+
+auto Server::ui_click_element(const char* tag, int index) -> bool {
+    return impl_->substrate != nullptr && impl_->substrate->click_element(tag, index);
+}
+
 void Server::ui_set_touch_override(UiTouchOverride ov) {
     if (impl_->substrate == nullptr) {
         return;