Primitives · a raise keeps its state under its owner's id

A raise inside another was namespaced by its place in the layer's
queue, so one that came before it moved its id path and rebuilt its
keyed state and focus: an open date popup would lose its month when a
tip appeared. raise now takes its owner's id and draws under it, and
float and float_height pass the owner's id on from every call site.
A test holds a focused box in a raise while another comes before it.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

src/forms/date/time.rs

@@ -256,6 +256,7 @@ impl RenderOnce for TimePicker {
                 let columns = time_columns(&id, time, step, commit.clone(), window, cx);
                 let out = close.clone();
                 float(
+                    id.clone(),
                     anchor,
                     CALENDAR_ROWS,
                     surface((id.clone(), "popup"), cx)
@@ -368,6 +369,7 @@ impl RenderOnce for DateTimePicker {
                 );
                 let out = close.clone();
                 float(
+                    id.clone(),
                     anchor,
                     CALENDAR_ROWS,
                     surface((id.clone(), "popup"), cx)