refactor(gui): todos ride the generic projection pair; ConversationSnapshot evacuated

TodoDock reads useProjection('todos') (whole list or null pre-first-write;
absent renders nothing) and declare-merges the todos key through the pure-type
outlet — the identical member the tool-todo host unit owns, drift rejected by
any program holding both. The core Session's todos field, its todo/write case,
and the snapshot member retire; the client folds nothing. Session specs for
the retired client fold move to the value-store spec's seq coverage; snapshot
literals across component specs drop the field.

packages/client/ui-conversation/tests/chat-code-subcalls.spec.tsx

@@ -56,7 +56,7 @@ function snapshotWith(
 ): ConversationSnapshot {
   return {
     sessionId: SID, nodes, foldDegraded: false, partial: null, runningCalls, codeDispatches,
-    pending: [], queue: [], todos: [], running: runningCalls.length > 0, composerPhase: 'active', removed: false,
+    pending: [], queue: [], running: runningCalls.length > 0, composerPhase: 'active', removed: false,
     openState: 'open', openError: null,
     hasMore: false, loadingOlder: false, promptError: null, blank: false, lastAgentError: null,
   }

packages/client/ui-conversation/tests/chat-stats-bash-sample.spec.tsx

@@ -27,7 +27,7 @@ const assistant = (seq: number, turn: number, usage?: unknown): AssistantMessage
 function snapshotBase(): ConversationSnapshot {
   return {
     sessionId: SID, nodes: [], foldDegraded: false, partial: null, runningCalls: [], codeDispatches: new Map(),
-    pending: [], queue: [], todos: [], running: false, composerPhase: 'active', removed: false, openState: 'open', openError: null,
+    pending: [], queue: [], running: false, composerPhase: 'active', removed: false, openState: 'open', openError: null,
     hasMore: false, loadingOlder: false, promptError: null, blank: false, lastAgentError: null,
   }
 }

packages/client/ui-conversation/tests/chat-toolview-slot.spec.tsx

@@ -40,7 +40,7 @@ const toolResult = (seq: number, callId: string, name: string, args = '{"command
 function snapshotWith(nodes: ToolResultNode[]): ConversationSnapshot {
   return {
     sessionId: SID, nodes, foldDegraded: false, partial: null, runningCalls: [], codeDispatches: new Map(),
-    pending: [], queue: [], todos: [], running: false, composerPhase: 'active', removed: false, openState: 'open', openError: null,
+    pending: [], queue: [], running: false, composerPhase: 'active', removed: false, openState: 'open', openError: null,
     hasMore: false, loadingOlder: false, promptError: null, blank: false, lastAgentError: null,
   }
 }

packages/client/ui-conversation/tests/chat-view.spec.tsx

@@ -30,7 +30,7 @@ const SID = 's1' as SessionId
 function snapshotBase(): ConversationSnapshot {
   return {
     sessionId: SID, nodes: [], foldDegraded: false, partial: null, runningCalls: [], codeDispatches: new Map(),
-    pending: [], queue: [], todos: [], running: false, composerPhase: 'active', removed: false, openState: 'open', openError: null,
+    pending: [], queue: [], running: false, composerPhase: 'active', removed: false, openState: 'open', openError: null,
     hasMore: false, loadingOlder: false, promptError: null, blank: false, lastAgentError: null,
   }
 }

packages/client/ui-conversation/tests/gate-branch-tails.spec.tsx

@@ -19,7 +19,7 @@ const SID = 's1' as SessionId
 function snapshotBase(): ConversationSnapshot {
   return {
     sessionId: SID, nodes: [], foldDegraded: false, partial: null, runningCalls: [], codeDispatches: new Map(),
-    pending: [], queue: [], todos: [], running: false, composerPhase: 'active', removed: false, openState: 'open', openError: null,
+    pending: [], queue: [], running: false, composerPhase: 'active', removed: false, openState: 'open', openError: null,
     hasMore: false, loadingOlder: false, promptError: null, blank: false, lastAgentError: null,
   }
 }

packages/client/ui-conversation/tests/input-bar.spec.tsx

@@ -21,7 +21,7 @@ const SID = 's1' as SessionId
 function snapshotOf(overrides: Partial<ConversationSnapshot> = {}): ConversationSnapshot {
   return {
     sessionId: SID, nodes: [], foldDegraded: false, partial: null, runningCalls: [], codeDispatches: new Map(),
-    pending: [], queue: [], todos: [], running: false, composerPhase: 'active', removed: false,
+    pending: [], queue: [], running: false, composerPhase: 'active', removed: false,
     openState: 'open', openError: null, hasMore: false, loadingOlder: false,
     promptError: null, blank: false, lastAgentError: null,
     ...overrides,

packages/client/ui-conversation/tests/input-matrix.spec.tsx

@@ -24,7 +24,7 @@ const SID = 's1' as SessionId
 function mountBar(shell: SessionInputShell, over?: { running?: boolean; disabled?: boolean }) {
   const session = createSnapshotStore<ConversationSnapshot>({
     sessionId: SID, nodes: [], foldDegraded: false, partial: null, runningCalls: [], codeDispatches: new Map(),
-    pending: [], queue: [], todos: [], running: over?.running ?? false, composerPhase: 'active',
+    pending: [], queue: [], running: over?.running ?? false, composerPhase: 'active',
     removed: over?.disabled ?? false, openState: 'open', openError: null, hasMore: false,
     loadingOlder: false, promptError: null, blank: false, lastAgentError: null,
   })

packages/client/ui-conversation/tests/input-scenarios.spec.tsx

@@ -110,7 +110,7 @@ async function scopedBench(register?: (slash: SlashService) => void) {
   const wiring = shell
   const sessionStore = createSnapshotStore<ConversationSnapshot>({
     sessionId, nodes: [], foldDegraded: false, partial: null, runningCalls: [], codeDispatches: new Map(),
-    pending: [], queue: [], todos: [], running: false, composerPhase: 'active', removed: false,
+    pending: [], queue: [], running: false, composerPhase: 'active', removed: false,
     openState: 'open', openError: null, hasMore: false, loadingOlder: false,
     promptError: null, blank: false, lastAgentError: null,
   })

packages/client/ui-conversation/tests/queue-dock.spec.tsx

@@ -19,7 +19,7 @@ const SID = 's1' as SessionId
 function snapshotWith(queue: QueuedMessage[]): ConversationSnapshot {
   return {
     sessionId: SID, nodes: [], foldDegraded: false, partial: null, runningCalls: [], codeDispatches: new Map(),
-    pending: [], queue, todos: [], running: true, composerPhase: 'active', removed: false, openState: 'open', openError: null,
+    pending: [], queue, running: true, composerPhase: 'active', removed: false, openState: 'open', openError: null,
     hasMore: false, loadingOlder: false, promptError: null, blank: false, lastAgentError: null,
   }
 }

packages/client/ui-conversation/tests/skeleton.spec.tsx

@@ -48,7 +48,7 @@ const workspaceState = (items: readonly WorkspaceView[]): WorkspaceListState =>
 function conversationSnapshot(overrides: Partial<ConversationSnapshot> = {}): ConversationSnapshot {
   return {
     sessionId: SID, nodes: [], foldDegraded: false, partial: null, runningCalls: [], codeDispatches: new Map(),
-    pending: [], queue: [], todos: [], running: false, composerPhase: 'active', removed: false,
+    pending: [], queue: [], running: false, composerPhase: 'active', removed: false,
     openState: 'open', openError: null, hasMore: false, loadingOlder: false,
     promptError: null, blank: false, lastAgentError: null,
     ...overrides,

packages/client/ui-conversation/tests/todo-panel.spec.tsx

@@ -64,20 +64,23 @@ describe('TodoPanel', () => {
   })
 })
 
-/** Dock props stub: the adapter reads useSession only; the rest of the owner share is unused. */
-function dockProps(store: ReturnType<typeof createSnapshotStore<{ todos: readonly TodoItem[] }>>): TodoDockProps {
-  return { useSession: bindSnapshotSelector(store) } as unknown as TodoDockProps
+/** Dock props stub: the adapter reads the 'todos' projection only; the rest of the owner share is unused. */
+function dockProps(store: ReturnType<typeof createSnapshotStore<{ value: readonly TodoItem[] | null | undefined }>>): TodoDockProps {
+  const useProjection = (_key: string, selector?: (v: unknown) => unknown) =>
+    bindSnapshotSelector(store)(s => (selector ?? (v => v))(s.value))
+  return { useProjection } as unknown as TodoDockProps
 }
 
 describe('TodoDock', () => {
-  it('selects the plan off the session snapshot and follows later writes', () => {
-    const store = createSnapshotStore<{ todos: readonly TodoItem[] }>({ todos: [] })
+  it('reads the host-computed todos projection and follows pushed updates', () => {
+    const store = createSnapshotStore<{ value: readonly TodoItem[] | null | undefined }>({ value: undefined })
     render(<TodoDock {...dockProps(store)} />)
+    // Capability absent (no baseline/frame yet) renders nothing.
     expect(screen.queryByTestId('todo-panel')).toBeNull()
-    act(() => { store.set({ todos: LIST }) })
+    act(() => { store.set({ value: LIST }) })
     expect(screen.getByText('1/3 tasks · 1 in progress')).toBeTruthy()
-    // A rollback to the empty list retires the strip (the panel owns no data).
-    act(() => { store.set({ todos: [] }) })
+    // The pre-first-write whole value (null) retires the strip (the panel owns no data).
+    act(() => { store.set({ value: null }) })
     expect(screen.queryByTestId('todo-panel')).toBeNull()
   })