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

examples/tui-agent/tests/tui.snapshot.ts

@@ -268,9 +268,6 @@ async function runScenario(scenario: Scenario): Promise<ScenarioResult> {
       color: true,
       showReasoning: true,
       title: 'DSH TUI snapshot',
-      // Off so replay stays deterministic: an auto-title request is not among the
-      // recorded turns. Auto-title's PTY coverage lives in the keyless smoke.
-      autoTitle: false,
       welcome: `Recorded replay: ${scenario.name}`,
       maxToolOutputLines: 8,
     }, {