fix(tui): slash.exec _pending_input commands, tool ANSI, terminal title

Additional TUI fixes discovered in the same audit:

1. /plan slash command was silently lost — process_command() queues the
   plan skill invocation onto _pending_input which nobody reads in the
   slash worker subprocess.  Now intercepted in slash.exec and routed
   through command.dispatch with a new 'send' dispatch type.

   Same interception added for /retry, /queue, /steer as safety nets
   (these already have correct TUI-local handlers in core.ts, but the
   server-side guard prevents regressions if the local handler is
   bypassed).

2. Tool results were stripping ANSI escape codes — the messageLine
   component used stripAnsi() + plain <Text> for tool role messages,
   losing all color/styling from terminal, search_files, etc.  Now
   uses <Ansi> component (already imported) when ANSI is detected.

3. Terminal tab title now shows model + busy status via useTerminalTitle
   hook from @hermes/ink (was never used).  Users can identify Hermes
   tabs and see at a glance whether the agent is busy or ready.

4. Added 'send' variant to CommandDispatchResponse type + asCommandDispatch
   parser + createSlashHandler handler for commands that need to inject
   a message into the conversation (plan, queue fallback, steer fallback).

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

@@ -152,6 +152,36 @@ describe('createSlashHandler', () => {
     })
     expect(ctx.transcript.send).toHaveBeenCalledWith(skillMessage)
   })
+
+  it('handles send-type dispatch for /plan command', async () => {
+    const planMessage = 'Plan skill content loaded'
+
+    const ctx = buildCtx({
+      gateway: {
+        gw: {
+          getLogTail: vi.fn(() => ''),
+          request: vi.fn((method: string) => {
+            if (method === 'slash.exec') {
+              return Promise.reject(new Error('pending-input command'))
+            }
+
+            if (method === 'command.dispatch') {
+              return Promise.resolve({ type: 'send', message: planMessage })
+            }
+
+            return Promise.resolve({})
+          })
+        },
+        rpc: vi.fn(() => Promise.resolve({}))
+      }
+    })
+
+    const h = createSlashHandler(ctx)
+    expect(h('/plan create a REST API')).toBe(true)
+    await vi.waitFor(() => {
+      expect(ctx.transcript.send).toHaveBeenCalledWith(planMessage)
+    })
+  })
 })
 
 const buildCtx = (overrides: Partial<Ctx> = {}): Ctx => ({