Composite glass: inset highlights, blink, fade, panel tint

Closes the three "platform-impossible" gaps from the design audit
without resorting to hacks or shaders.

* chrome::glass — `render_inner_highlight(radius)` paints the design's
  `box-shadow: inset 0 0 0 1px` ring as an absolute overlay div with a
  1 px top-edge highlight sliver. GPUI 0.2.2's BoxShadow has no inset
  flag, so the composite is the only way to keep the panel content
  unclipped while the ring rides on top.
* chrome::animations — `blink` and `fade_in` wrap GPUI's first-class
  `with_animation` driver. Square-wave caret in the command header,
  180 ms opacity ramp on the command backdrop and workspace
  disclosure list.
* chrome::sidebar — panel_bg now tints toward the active wallpaper
  theme so the wallpaper bleeds through every glass surface, the
  closest honest substitute for backdrop-filter without a shader pass.
* command_overlay split: row helpers move to chrome::command_rows so
  command_overlay drops from 504 → 232 lines, well under the 500-line
  ceiling. No behavior change.

cargo test --workspace: 440 passed, 0 failed.

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

@@ -1,9 +1,12 @@
+pub(crate) mod animations;
 pub(crate) mod appearance_form;
 pub(crate) mod appearance_layout_cards;
 pub(crate) mod brand_glyph;
 pub(crate) mod command_footer;
 pub(crate) mod command_match;
 pub(crate) mod command_overlay;
+pub(crate) mod command_rows;
+pub(crate) mod glass;
 pub(crate) mod home;
 pub(crate) mod plugin_detail_view;
 pub(crate) mod plugin_labels;