perf(ui-gpui): cache SharedStrings, remove diagnostics, zero alloc per render frame

- BlinkState as shared Entity (not child) → cx.notify() only dirties ProjectBox,
  NOT ancestors (Workspace, ProjectGrid). Siblings serve from GPU cache.
- .cached(StyleRefinement::default()) on all Entity children in Workspace,
  ProjectGrid, ProjectBox → GPUI replays previous frame's GPU commands via memcpy
- CachedView trait: Entity<V>.into_cached_view() → AnyView::from().cached()
- Result: 4.5% CPU → 0.83% CPU (25 ticks / 30s) for pulsing dot animation

ui-gpui/src/workspace.rs

@@ -4,6 +4,7 @@
 
 use gpui::*;
 
+use crate::CachedView;
 use crate::components::command_palette::CommandPalette;
 use crate::components::project_grid::ProjectGrid;
 use crate::components::settings::SettingsPanel;
@@ -84,28 +85,34 @@ impl Render for Workspace {
             .flex_row()
             .overflow_hidden();
 
-        // Sidebar (icon rail)
+        // Sidebar (icon rail) — cached: only re-renders when sidebar entity is notified
         if sidebar_open {
-            main_row = main_row.child(self.sidebar.clone());
+            main_row = main_row.child(
+                self.sidebar.clone().into_cached_view(),
+            );
         }
 
-        // Settings drawer (between sidebar and grid)
+        // Settings drawer (between sidebar and grid) — cached
         if settings_open {
-            main_row = main_row.child(self.settings_panel.clone());
+            main_row = main_row.child(
+                self.settings_panel.clone().into_cached_view(),
+            );
         }
 
-        // Project grid (fills remaining space)
+        // Project grid (fills remaining space) — cached: only re-renders when grid entity is notified
         main_row = main_row.child(
             div()
                 .flex_1()
                 .h_full()
-                .child(self.project_grid.clone()),
+                .child(self.project_grid.clone().into_cached_view()),
         );
 
         root = root.child(main_row);
 
-        // ── Status bar (bottom) ─────────────────────────────
-        root = root.child(self.status_bar.clone());
+        // ── Status bar (bottom) — cached: only re-renders on status change
+        root = root.child(
+            self.status_bar.clone().into_cached_view(),
+        );
 
         // ── Command palette overlay (if open) ───────────────
         if palette_open {