Restructure topbar to match design's omnibar + right action cluster

Move topbar rendering into chrome::topbar so it does not bloat render.rs.
The omnibar now ends in two glass chips (filters + favorite star) inline
with the address input, matching the design's pill layout. The toolbar
right cluster is rebuilt as copy-url, downloads, theme, and menu icons:

- Copy chip writes the active tab's URL to the system clipboard.
- Downloads opens ely://downloads (existing internal route).
- Theme chip routes to ely://settings/appearance for now (a Light/Dark
  toggle still has to live in appearance settings before it can be a
  one-shot).
- Menu opens ely://settings.

The pin/new-tab buttons are removed; they were not part of the design's
topbar. Pinning still works through the favorite chip + sidebar
selection state, and Cmd+T continues to create tabs.

crates/ely_app/src/shell/chrome/mod.rs

@@ -1,5 +1,7 @@
 pub(crate) mod sidebar_header;
+pub(crate) mod topbar;
 pub(crate) mod wallpaper;
 
 pub(crate) use sidebar_header::render_sidebar_header;
+pub(crate) use topbar::render_topbar;
 pub(crate) use wallpaper::{WallpaperTheme, render_wallpaper};