fix(tui): release the adapter-registration listener on channel detach

Review follow-up: the llm/adapters-updated listener's disposer was
discarded, leaving it firing (harmlessly, behind isDisposed()) between
TUI shutdown and fiber disposal, asymmetric with the sibling channel
listeners. The controller now exposes detach(), and the channel's
detachListeners() calls it on both the dispose() and startup-failure
paths.

packages/ui/tui/tests/tui.spec.ts

@@ -3671,6 +3671,31 @@ describe('pi-tui chat lifecycle and transcript', () => {
     await dispose(result)
   })
 
+  it('stops listening for adapter registrations after channel detach', async () => {
+    // The listener disposer rides detachListeners() through the controller's
+    // detach(): after dispose, a registry commit must not re-enter resolution
+    // at all (the isDisposed() guard is a fallback, not the removal).
+    const calls: string[] = []
+    const result = await setup({
+      agentOptions: { provider: 'openai-codex', model: 'gpt-x' },
+      catalog: {
+        providers: [],
+        models: [],
+        resolveModelInfo: (provider) => {
+          calls.push(provider)
+          return Promise.reject(new LlmError('no adapter registered for provider "openai-codex"', 'NO_ADAPTER'))
+        },
+      },
+    })
+    await tick()
+    const callsAtDetach = calls.length
+    await result.controller.dispose()
+    result.ctx.emit('llm/adapters-updated')
+    await tick()
+    expect(calls.length).toBe(callsAtDetach)
+    await result.ctx.fiber.dispose()
+  })
+
   it('drops a deferred NO_ADAPTER resolution when the target moved before the adapter registered', async () => {
     const result = await setup({
       agentOptions: { provider: 'openai-codex', model: 'gpt-x' },