feat(web): add session model selector

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

@@ -29,6 +29,7 @@ function snapshotBase(): ConversationSnapshot {
     sessionId: SID, nodes: [], foldDegraded: false, partial: null, runningCalls: [],
     pending: [], running: false, removed: false, openState: 'open', openError: null,
     hasMore: false, loadingOlder: false, promptError: null, lastAgentError: null,
+    modelSelection: { current: null, groups: [], failures: [], status: 'idle', error: null },
   }
 }
 

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

@@ -41,7 +41,8 @@ function snapshotWith(nodes: ToolResultNode[]): ConversationSnapshot {
     sessionId: SID, nodes, foldDegraded: false, partial: null, runningCalls: [],
     pending: [], running: false, removed: false, openState: 'open', openError: null,
     hasMore: false, loadingOlder: false, promptError: null, lastAgentError: null,
-  } as ConversationSnapshot
+    modelSelection: { current: null, groups: [], failures: [], status: 'idle', error: null },
+  }
 }
 
 /** Test-owned AppFrame role: declares the layout-owned children and renders the conversation area under the framework session provider. */

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

@@ -31,6 +31,7 @@ function snapshotBase(): ConversationSnapshot {
     sessionId: SID, nodes: [], foldDegraded: false, partial: null, runningCalls: [],
     pending: [], running: false, removed: false, openState: 'open', openError: null,
     hasMore: false, loadingOlder: false, promptError: null, lastAgentError: null,
+    modelSelection: { current: null, groups: [], failures: [], status: 'idle', error: null },
   }
 }
 

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

@@ -26,7 +26,8 @@ function snapshotBase(): ConversationSnapshot {
     sessionId: SID, nodes: [], foldDegraded: false, partial: null, runningCalls: [],
     pending: [], running: false, removed: false, openState: 'open', openError: null,
     hasMore: false, loadingOlder: false, promptError: null, lastAgentError: null,
-  } as ConversationSnapshot
+    modelSelection: { current: null, groups: [], failures: [], status: 'idle', error: null },
+  }
 }
 
 describe('render branch tails', () => {

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

@@ -128,4 +128,11 @@ describe('error strip and variants', () => {
     expect(view.getByTestId('acc')).toBeTruthy()
     expect(view.container.querySelector('[class*="hero"]')).not.toBeNull()
   })
+
+  it('renders the optional composer control immediately before the primary button', () => {
+    const { view } = setup({ control: <button type="button">model</button> })
+    const buttons = view.getAllByRole('button')
+    expect(buttons.map(button => button.textContent)).toEqual(['model', ''])
+    expect(buttons[1]?.getAttribute('aria-label')).toBe('发送')
+  })
 })

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

@@ -30,7 +30,8 @@ function snapshotBase(): ConversationSnapshot {
     sessionId: SID, nodes: [], foldDegraded: false, partial: null, runningCalls: [],
     pending: [], running: false, removed: false, openState: 'open', openError: null,
     hasMore: false, loadingOlder: false, promptError: null, lastAgentError: null,
-  } as ConversationSnapshot
+    modelSelection: { current: null, groups: [], failures: [], status: 'idle', error: null },
+  }
 }
 
 function sessionSource(over?: Partial<ConversationSnapshot>) {
@@ -58,7 +59,9 @@ function listHook(rows: { id: string; title: string; cwd?: string; parentId?: st
 describe('ConversationRoot branches', () => {
   const chatTab: ViewTab = { id: 'chat', label: 'Chat' }
   /** renderSlot stub in the outlet's baked shape (ring key + only filter marker). */
-  const stubRenderSlot = (() => <div data-testid="view-body" />) as unknown as ConversationRootProps['renderSlot']
+  const stubRenderSlot = ((key: string) =>
+    key === 'conversation.view' ? <div data-testid="view-body" /> : null
+  ) as unknown as ConversationRootProps['renderSlot']
   /** SessionProvider seat stub (render-prop pass-through; ConversationRoot never invokes it). */
   const SessionProviderStub: ConversationRootProps['SessionProvider'] = ({ children }) => <>{children(SID)}</>
 

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

@@ -177,8 +177,11 @@ describe('ConversationRoot', () => {
   })
 
   it('hides the tab strip with a single view; composer writes the store draft and sends it', () => {
-    const { chat, send } = bench([tab('chat', 'Chat')])
+    const { chat, send, renderSlot } = bench([tab('chat', 'Chat')])
     expect(screen.queryByRole('tablist')).toBeNull()
+    expect(renderSlot).toHaveBeenCalledWith('conversation.composer.control', {})
+    expect(screen.getByTestId('view-(all)').getAttribute('data-slot'))
+      .toBe('conversation.composer.control')
     const box = screen.getByPlaceholderText(/输入消息/)
     fireEvent.change(box, { target: { value: 'hi' } })
     // Typing goes through actions.setDraft into the shared store.