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).

tests/tui_gateway/test_protocol.py

@@ -258,6 +258,72 @@ def test_slash_exec_rejects_skill_commands(server):
     assert "skill command" in resp["error"]["message"]
 
 
+@pytest.mark.parametrize("cmd", ["retry", "queue hello", "q hello", "steer fix the test", "plan"])
+def test_slash_exec_rejects_pending_input_commands(server, cmd):
+    """slash.exec must reject commands that use _pending_input in the CLI."""
+    sid = "test-session"
+    server._sessions[sid] = {"session_key": sid, "agent": None}
+
+    resp = server.handle_request({
+        "id": "r1",
+        "method": "slash.exec",
+        "params": {"command": cmd, "session_id": sid},
+    })
+
+    assert "error" in resp
+    assert resp["error"]["code"] == 4018
+    assert "pending-input command" in resp["error"]["message"]
+
+
+def test_command_dispatch_queue_sends_message(server):
+    """command.dispatch /queue returns {type: 'send', message: ...} for the TUI."""
+    sid = "test-session"
+    server._sessions[sid] = {"session_key": sid}
+
+    resp = server.handle_request({
+        "id": "r1",
+        "method": "command.dispatch",
+        "params": {"name": "queue", "arg": "tell me about quantum computing", "session_id": sid},
+    })
+
+    assert "error" not in resp
+    result = resp["result"]
+    assert result["type"] == "send"
+    assert result["message"] == "tell me about quantum computing"
+
+
+def test_command_dispatch_queue_requires_arg(server):
+    """command.dispatch /queue without an argument returns an error."""
+    sid = "test-session"
+    server._sessions[sid] = {"session_key": sid}
+
+    resp = server.handle_request({
+        "id": "r2",
+        "method": "command.dispatch",
+        "params": {"name": "queue", "arg": "", "session_id": sid},
+    })
+
+    assert "error" in resp
+    assert resp["error"]["code"] == 4004
+
+
+def test_command_dispatch_steer_fallback_sends_message(server):
+    """command.dispatch /steer with no active agent falls back to send."""
+    sid = "test-session"
+    server._sessions[sid] = {"session_key": sid, "agent": None}
+
+    resp = server.handle_request({
+        "id": "r3",
+        "method": "command.dispatch",
+        "params": {"name": "steer", "arg": "focus on testing", "session_id": sid},
+    })
+
+    assert "error" not in resp
+    result = resp["result"]
+    assert result["type"] == "send"
+    assert result["message"] == "focus on testing"
+
+
 def test_command_dispatch_returns_skill_payload(server):
     """command.dispatch returns structured skill payload for the TUI to send()."""
     sid = "test-session"