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/fixtures/tui-scripted-llm.ts

@@ -38,8 +38,9 @@ class ScriptedTuiAdapter extends LlmAdapter {
   }
 
   override async * stream(options: GenerateOptions): AsyncIterable<StreamChunk> {
-    // The TUI's auto-title request carries no tool schemas, unlike every agent
-    // turn; answer it with a fixed title so the PTY test can assert the OSC set.
+    // The session-title provider's auxiliary request carries no tool schemas,
+    // unlike every agent turn; answer it with a fixed title so the PTY test can
+    // assert the logged title reaches the terminal window title.
     if ((options.tools?.length ?? 0) === 0) {
       for (const chunk of textChunks(TITLE_TEXT)) yield chunk
       return

examples/tui-agent/tests/fixtures/tui-scripted.cordis.yml

@@ -30,4 +30,15 @@
     persona: 'Scripted model {{model}}.'
     ui:
       showReasoning: true
-      autoTitle: true
+
+# Model-made session titles, as in the shipped cordis.yml: the scripted adapter
+# answers the tool-less title request with a fixed string so the PTY test can
+# assert the logged title reaches the terminal window title.
+- id: session-title-llm
+  name: '@deepseek-ai/dsh-session-title-first-message-llm'
+  config:
+    targetWords: 5
+    targetCjkCharacters: 10
+    maxInputBytes: 4096
+    maxOutputTokens: 64
+    timeoutMs: 10000