fix: animate the workspace row-click expand/collapse

.claude/rules/sidebar.md

@@ -43,7 +43,10 @@ paths:
   toggle. This click routing is keep-in-sync exempt. `GhosttyApp.workspaceRowClickExpands` (default on)
   gates the whole-row target only; the disclosure triangle toggles natively and stays unconditional.
   The deferred item re-reads that mirror when it fires, so turning the setting off inside the deferral
-  window cancels the pending toggle. Control expansion instead persists through
+  window cancels the pending toggle. Route the row-click toggle through `outline.animator()` so it animates
+  like the triangle; a bare `expandItem`/`collapseItem` silently drops the animation. Do not gate that on
+  Reduce Motion — both hit targets reach the same AppKit animation, so a gate would re-split them. Every
+  other expand/collapse site stays unanimated: bulk or programmatic. Control expansion instead persists through
   `AppActions.setWorkspaceExpanded`, then posts `.agtermSetWorkspaceExpanded` to synchronize a live outline.
 - A session-row click selects, then asynchronously calls `revealActiveBlockedPane` with the captured
   pre-reset indicator. Blocked/completed pane tags reveal split, scratch, or primary; idle and active use

agterm/Views/WorkspaceSidebar+ContextMenu.swift

@@ -47,8 +47,12 @@ extension WorkspaceSidebar.Coordinator {
         renameController.beginEditing(node: node)
     }
 
+    /// Animated to match the disclosure triangle; `.claude/rules/sidebar.md` owns why, why it is not gated on
+    /// Reduce Motion, and which sites stay unanimated. The proxy fires didExpand/didCollapse synchronously, so
+    /// the persist write-back still runs and the other sites' `suppressExpansionPersist` brackets still hold.
     private func toggleExpansion(of node: SidebarNode, in outline: NSOutlineView) {
-        if outline.isItemExpanded(node) { outline.collapseItem(node) } else { outline.expandItem(node) }
+        let proxy = outline.animator()
+        if outline.isItemExpanded(node) { proxy.collapseItem(node) } else { proxy.expandItem(node) }
     }
 
     /// Builds the per-row context menu, resolving the clicked row lazily so one menu serves every row.

docs/backlog/workspace-row-toggle-deferral-drops-clicks.md

@@ -0,0 +1,40 @@
+---
+worth: later
+where: agterm/Views/WorkspaceSidebar+ContextMenu.swift:15
+added: 2026-08-09
+---
+# the deferred workspace-row toggle drops one click and fires another under the wrong row
+
+`handleSingleClick` parks the toggle in a single `pendingRowToggle` slot for `NSEvent.doubleClickInterval`
+so a rename double-click can cancel it. Two consequences fall out of the guard ordering, both reachable
+with ordinary clicking:
+
+- **A click on a second workspace row eats the first.** The `pendingRowToggle?.cancel()` at line 28 is
+  unconditional and the slot holds one item, so clicking workspace A's row and then workspace B's inside
+  the interval cancels A and toggles only B. A's click is gone with nothing on screen to say so.
+- **A session-row click does not disarm a pending workspace toggle.** The guard at lines 17-18 returns for
+  `node.kind == .session` before reaching that cancel, so clicking workspace A and then a session in
+  another workspace selects the session immediately and then, a beat later, expands A underneath it and
+  shifts every row below.
+
+Both are worse than they look because a workspace row is not selectable
+(`WorkspaceSidebar+RowRendering.swift:15-18` returns `shouldSelectItem` only for sessions), so the whole
+deferral window carries no feedback at all - no pill, no press state, no disclosure movement. The click
+reads as dropped either way.
+
+Three approaches were weighed and none taken: drop double-click rename on workspace rows (rejected -
+double-click rename is the discoverable path and the macOS convention, whatever the other entry points);
+toggle optimistically and invert on double-click (rejected - trades a dead pause for a visible flicker on
+rename); and keep the deferral but add press feedback (rejected - a custom-drawn disclosure triangle or a
+transient row pill is too much machinery for the size of the defect). Revisit only if the delay starts
+costing more than it looks like it does.
+
+Not fixed alongside #407's animation because the fix is a behavior decision, not a rendering one. #407
+itself names the two candidates for the delay - toggle optimistically and reverse on a double-click, or
+move workspace rename off double-click - and either would settle these two as a side effect, while
+patching them in isolation (per-node pending toggles, or hoisting the cancel above the guards) preserves
+a half-second of silent latency that is itself the complaint.
+
+Worth weighing that workspace rename already has five other entry points - the row context menu, the File
+menu's Workspace section, the `rename_workspace` built-in, the command palette, and `workspace.rename` -
+so the deferral protects a sixth path to something already well covered.