Tables: focused headers scroll into view; long tables scroll sideways

A sortable header is a tracked Tab stop; once focused it sets its
table's sideways offset whole from its painted bounds and asks one
frame. The virtualized branch scrolls sideways too, and its list
keeps a plain wheel to its rows. layout::on_axis keeps a scroll box's
wheel to its axes; tables, code blocks, the thumbnail strip and the
gallery's page use it. Footer figures move to tables/foot.rs; the
profiler's ruler takes theme.chart().label. HumanInputRequest's
answered state gets a test.

examples/gallery/shell.rs

@@ -1,5 +1,6 @@
 use ely_gpui_component::{
     buttons::{ButtonVariant, IconButton},
+    layout::on_axis,
     primitives::{FocusScope, IconName},
     theme::{ActiveTheme, ControlSize, Mode, Radius, TextSize, Theme},
 };
@@ -122,8 +123,7 @@ impl Gallery {
                     ),
             )
             .child(
-                div()
-                    .id("nav")
+                on_axis(div().id("nav"))
                     .flex()
                     .flex_col()
                     .gap_0p5()
@@ -208,8 +208,7 @@ impl Render for Gallery {
             .text_size(theme.text_size(TextSize::Base))
             .child(sidebar)
             .child(
-                div()
-                    .id("page")
+                on_axis(div().id("page"))
                     .flex_1()
                     .h_full()
                     .overflow_y_scroll()