fix(tui): persist model switches by default

ui-tui/src/__tests__/createSlashHandler.test.ts

@@ -25,6 +25,36 @@ describe('createSlashHandler', () => {
     expect(ctx.gateway.gw.request).not.toHaveBeenCalled()
   })
 
+  it('persists typed /model switches by default', async () => {
+    patchUiState({ sid: 'sid-abc' })
+
+    const ctx = buildCtx({
+      gateway: {
+        ...buildGateway(),
+        rpc: vi.fn(() => Promise.resolve({ value: 'x-model' }))
+      }
+    })
+
+    expect(createSlashHandler(ctx)('/model x-model')).toBe(true)
+    expect(ctx.gateway.rpc).toHaveBeenCalledWith('config.set', {
+      key: 'model',
+      session_id: 'sid-abc',
+      value: 'x-model --global'
+    })
+  })
+
+  it('does not duplicate --global for explicit persistent model switches', () => {
+    patchUiState({ sid: 'sid-abc' })
+    const ctx = buildCtx()
+
+    createSlashHandler(ctx)('/model x-model --global')
+    expect(ctx.gateway.rpc).toHaveBeenCalledWith('config.set', {
+      key: 'model',
+      session_id: 'sid-abc',
+      value: 'x-model --global'
+    })
+  })
+
   it('opens the skills hub locally for bare /skills', () => {
     const ctx = buildCtx()