opentui(phase3): launcher integration — HERMES_TUI_ENGINE dual-engine

hermes --tui launches the native OpenTUI engine (Bun) when
HERMES_TUI_ENGINE=opentui (env) or display.tui_engine=opentui (config);
Ink stays the default and the shipping path is untouched.

- _resolve_tui_engine() (env > config > ink); refuses opentui on
  Windows/Termux (no Bun) -> falls back to ink with a notice.
- _make_opentui_argv() -> [bun, src/entry.real.tsx] (no build step).
- _bun_bin() with HERMES_BUN override.
- Branch at top of _make_tui_argv BEFORE _ensure_tui_node (Bun-only host
  must not bootstrap Node).
- Gate _launch_tui NODE_OPTIONS/--max-old-space-size on engine==ink (Bun
  is JSC; the V8 flag errors/ignores).

Verified end-to-end via tmux: real hermes --tui -> Bun -> OpenTUI ->
real Python gateway streamed a real reply. No-flag default still ink.

cli-config.yaml.example

@@ -415,8 +415,7 @@ prompt_caching:
 # Auxiliary Models (Advanced — Experimental)
 # =============================================================================
 # Hermes uses lightweight "auxiliary" models for side tasks: image analysis,
-# browser screenshot analysis, web page summarization, TTS audio-tag insertion,
-# and context compression.
+# browser screenshot analysis, web page summarization, and context compression.
 #
 # By default these use Gemini Flash via OpenRouter or Nous Portal and are
 # auto-detected from your credentials.  You do NOT need to change anything
@@ -461,12 +460,6 @@ prompt_caching:
 #     provider: "auto"
 #     model: ""
 #
-#   # Gemini 3.1 TTS hidden audio-tag insertion
-#   tts_audio_tags:
-#     provider: "auto"       # empty model = your main chat model
-#     model: ""
-#     timeout: 30
-#
 #   # Session search — summarizes matching past sessions
 #   session_search:
 #     provider: "auto"
@@ -535,15 +528,6 @@ session_reset:
   idle_minutes: 1440   # Inactivity timeout in minutes (default: 1440 = 24 hours)
   at_hour: 4           # Daily reset hour, 0-23 local time (default: 4 AM)
 
-# Maximum number of simultaneously active chat sessions across CLI, TUI,
-# dashboard chat, and messaging gateway. Set to null, 0, or omit to allow
-# unlimited concurrent sessions. When the limit is reached, new sessions get a
-# clean error while existing active sessions keep their normal behavior. This
-# top-level key takes precedence over gateway.max_concurrent_sessions. The cap
-# is a best-effort single-host/profile runtime guard; Hermes fails open if the
-# local runtime lease registry cannot be read or locked.
-max_concurrent_sessions: null
-
 # When true, group/channel chats use one session per participant when the platform
 # provides a user ID. This is the secure default and prevents users in the same
 # room from sharing context, interrupts, and token costs. Set false only if you
@@ -842,22 +826,6 @@ platform_toolsets:
 #       max_tool_rounds: 5      # tool loop limit (0 = disable)
 #       log_level: "info"       # audit verbosity
 
-# =============================================================================
-# Text-to-Speech
-# =============================================================================
-# TTS defaults to Edge TTS unless changed in ~/.hermes/config.yaml.
-# Gemini TTS supports persona/director prompt files, and Gemini 3.1 Flash TTS
-# can use a hidden auxiliary rewrite pass to insert expressive square-bracket
-# audio tags into the TTS script without showing tags in chat.
-#
-# tts:
-#   provider: "gemini"
-#   gemini:
-#     model: "gemini-3.1-flash-tts-preview"
-#     voice: "Kore"
-#     audio_tags: false
-#     persona_prompt_file: ""  # e.g. ~/.hermes/tts/radio-host.md
-
 # =============================================================================
 # Voice Transcription (Speech-to-Text)
 # =============================================================================