refactor(tui): drop the TUI-local auto-title; titles come from the session-title service

Master's log-backed session-title capability already titles sessions durably
(deterministic fallback in the spine, optional model providers). Remove the
TUI's own autoTitle generation — the latch, prompt, cap, and llm stream call —
and keep the terminal rename: the TUI folds the logged title on mount and sets
'<session title> — <configured title>' on every accepted session/title event.
The tui-agent example and the scripted PTY fixture mount
session-title-first-message-llm so titles stay model-made; the scripted
adapter's tool-less branch now answers that provider's auxiliary request.

See .agents/notes/implemented/simplification/2026-07-22-tui-titles-from-session-title-service.md

packages/ui/tui/README.md

@@ -42,7 +42,6 @@ When `resumeCommand` is set and a `sessionPersistence` backend is mounted, exiti
 | `color` | `true` | Apply the built-in ANSI palette (see [Color](#color)) |
 | `title` | `DeepSeek Harness` | Product suffix for the terminal window title. |
 | `resumeCommand` | — | Shell command template for the exit hint and `/resume`, with `{session}` expanded to the session id; unset disables both. Needs a `sessionPersistence` backend |
-| `autoTitle` | `true` | Replace `title` with a short model-made title derived from the session's first user message; a resumed session re-derives it from that stored message on mount (needs an `llm` service and an agent provider/model) |
 
 ```yaml
 - id: terminal