feat(app): persist todo dock collapsed state (#26953)

packages/app/src/context/layout.tsx

@@ -43,6 +43,7 @@ type SessionView = {
   reviewOpen?: string[]
   pendingMessage?: string
   pendingMessageAt?: number
+  todoCollapsed?: boolean
 }
 
 type TabHandoff = {
@@ -759,6 +760,18 @@ export const { use: useLayout, provider: LayoutProvider } = createSimpleContext(
           setScroll(tab: string, pos: SessionScroll) {
             scroll.setScroll(key(), tab, pos)
           },
+          todoCollapsed: {
+            get: () => s().todoCollapsed ?? false,
+            set(collapsed: boolean) {
+              const session = key()
+              const current = store.sessionView[session]
+              if (!current) {
+                setStore("sessionView", session, { scroll: {}, todoCollapsed: collapsed })
+              } else {
+                setStore("sessionView", session, "todoCollapsed", collapsed)
+              }
+            },
+          },
           terminal: {
             opened: terminalOpened,
             open() {