perf(ui-gpui): flatten hierarchy + SharedBlink (Arc<AtomicBool>)

- Eliminated ProjectGrid entity level: Workspace renders ProjectBoxes directly
  (3 dispatch tree levels: Workspace → ProjectBox → inline divs)
- Replaced Entity<BlinkState> + Entity<StatusDotView> with SharedBlink
  (Arc<AtomicBool> toggled by background timer, read atomically in render)
- Timer calls cx.notify() directly on ProjectBox (no intermediate entities)
- CPU: 2.93% (unchanged from 3.07% — confirms cost is ProjectBox::render()
  overhead, not hierarchy depth or entity count)
- Each blink frame: ~15ms total (render + layout + prepaint + paint + GPU submit)
- Zed comparison: ~5ms per blink frame (EditorElement is custom Element, not div tree)

ui-gpui/src/workspace.rs

@@ -1,25 +1,25 @@
-//! Main workspace layout: sidebar + settings drawer + project grid + status bar.
+//! Workspace: root view composing sidebar + project boxes + status bar.
 //!
-//! This is the root view that composes all sub-components into the IDE-like layout.
+//! ProjectBoxes are rendered DIRECTLY as children of Workspace (no intermediate
+//! ProjectGrid entity). This keeps the dispatch tree at 3 levels:
+//! Workspace → ProjectBox → StatusDotView (same depth as Zed's Workspace → Pane → Editor).
 
 use gpui::*;
 
-use crate::CachedView;
 use crate::components::command_palette::CommandPalette;
-use crate::components::project_grid::ProjectGrid;
+use crate::components::project_box::ProjectBox;
 use crate::components::settings::SettingsPanel;
 use crate::components::sidebar::Sidebar;
 use crate::components::status_bar::StatusBar;
 use crate::state::AppState;
 use crate::theme;
 
-// ── Workspace View ──────────────────────────────────────────────────
-
 pub struct Workspace {
+    #[allow(dead_code)]
     app_state: Entity<AppState>,
     sidebar: Entity<Sidebar>,
     settings_panel: Entity<SettingsPanel>,
-    project_grid: Entity<ProjectGrid>,
+    project_boxes: Vec<Entity<ProjectBox>>,
     status_bar: Entity<StatusBar>,
     command_palette: Entity<CommandPalette>,
 }
@@ -34,10 +34,6 @@ impl Workspace {
             let state = app_state.clone();
             |_cx| SettingsPanel::new(state)
         });
-        let project_grid = cx.new({
-            let state = app_state.clone();
-            |cx| ProjectGrid::new(state, cx)
-        });
         let status_bar = cx.new({
             let state = app_state.clone();
             |_cx| StatusBar::new(state)
@@ -47,14 +43,24 @@ impl Workspace {
             |_cx| CommandPalette::new(state)
         });
 
-        // NOTE: removed cx.observe(&app_state) — reading app_state.read(cx) in render
-        // already subscribes to changes. The observe was causing redundant re-renders.
+        // Create ProjectBoxes directly (no intermediate ProjectGrid entity)
+        let projects: Vec<_> = app_state.read(cx).projects.clone();
+        let project_boxes: Vec<Entity<ProjectBox>> = projects
+            .into_iter()
+            .map(|proj| {
+                cx.new(|cx| {
+                    let mut pb = ProjectBox::new(proj);
+                    pb.init_subviews(cx);
+                    pb
+                })
+            })
+            .collect();
 
         Self {
             app_state,
             sidebar,
             settings_panel,
-            project_grid,
+            project_boxes,
             status_bar,
             command_palette,
         }
@@ -62,8 +68,7 @@ impl Workspace {
 }
 
 impl Render for Workspace {
-    fn render(&mut self, _window: &mut Window, cx: &mut Context<Self>) -> impl IntoElement {
-        // Hardcoded layout state — avoids model subscription that causes re-renders
+    fn render(&mut self, _window: &mut Window, _cx: &mut Context<Self>) -> impl IntoElement {
         let sidebar_open = true;
         let settings_open = false;
         let palette_open = false;
@@ -76,7 +81,7 @@ impl Render for Workspace {
             .bg(theme::CRUST)
             .font_family("Inter");
 
-        // ── Main content row (sidebar + settings? + grid) ───
+        // Main content row
         let mut main_row = div()
             .id("main-row")
             .flex_1()
@@ -85,32 +90,34 @@ impl Render for Workspace {
             .flex_row()
             .overflow_hidden();
 
-        // Sidebar (icon rail) — uncached (tiny, cheap to render)
         if sidebar_open {
             main_row = main_row.child(self.sidebar.clone());
         }
-
-        // Settings drawer (between sidebar and grid)
         if settings_open {
             main_row = main_row.child(self.settings_panel.clone());
         }
 
-        // Project grid (fills remaining space) — cached with flex-1
-        // ProjectGrid cached — when StatusDotView notifies, ProjectGrid IS in dirty_views
-        // (ancestor walk), but the cached wrapper checks ProjectGrid's own entity_id.
-        // Since ProjectGrid wasn't directly notified, the cache should hit.
-        // Wait — mark_view_dirty inserts ALL ancestors including ProjectGrid.
-        // So the cache WILL miss for ProjectGrid. We need it uncached.
-        main_row = main_row.child(
-            div().flex_1().h_full().child(self.project_grid.clone()),
-        );
+        // Project grid area — inline, no intermediate entity
+        let mut grid = div()
+            .id("project-grid")
+            .flex_1()
+            .h_full()
+            .flex()
+            .flex_row()
+            .flex_wrap()
+            .gap(px(8.0))
+            .p(px(8.0))
+            .bg(theme::CRUST)
+            .overflow_y_scroll();
 
+        for pb in &self.project_boxes {
+            grid = grid.child(pb.clone());
+        }
+
+        main_row = main_row.child(grid);
         root = root.child(main_row);
-
-        // Status bar (bottom) — uncached (tiny, cheap to render)
         root = root.child(self.status_bar.clone());
 
-        // ── Command palette overlay (if open) ───────────────
         if palette_open {
             root = root.child(self.command_palette.clone());
         }