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.

toolsets.py

@@ -33,9 +33,6 @@ _HERMES_CORE_TOOLS = [
     "web_search", "web_extract",
     # Terminal + process management
     "terminal", "process",
-    # Read the desktop GUI's embedded terminal pane (gated on HERMES_DESKTOP
-    # via check_fn in tools/read_terminal_tool.py — hidden outside the GUI).
-    "read_terminal",
     # File manipulation
     "read_file", "write_file", "patch", "search_files",
     # Vision + image generation
@@ -339,33 +336,6 @@ TOOLSETS = {
         "tools": [],
         "includes": ["web", "vision", "image_gen"]
     },
-
-    # Coding posture (base Hermes — CLI/TUI/desktop/ACP). Auto-selected in a
-    # code workspace; see agent/coding_context.py. Keeps everything you reach
-    # for while pairing on code and drops the rest (messaging, tts, image_gen,
-    # spotify, home-assistant, cron, computer-use).
-    "coding": {
-        "description": "Coding-focused toolset: files, terminal, search, web docs, skills, todo, delegate, vision, browser",
-        "tools": [
-            "web_search", "web_extract",
-            "terminal", "process", "read_terminal",
-            "read_file", "write_file", "patch", "search_files",
-            "vision_analyze",
-            "skills_list", "skill_view", "skill_manage",
-            "browser_navigate", "browser_snapshot", "browser_click",
-            "browser_type", "browser_scroll", "browser_back",
-            "browser_press", "browser_get_images",
-            "browser_vision", "browser_console", "browser_cdp", "browser_dialog",
-            "todo", "memory",
-            "session_search", "clarify",
-            "execute_code", "delegate_task",
-        ],
-        "includes": [],
-        # Posture toolset: selected per-session by agent/coding_context.py,
-        # never auto-recovered into per-platform tool config (see the
-        # non-configurable-toolset recovery loop in hermes_cli/tools_config.py).
-        "posture": True,
-    },
     
     # ==========================================================================
     # Full Hermes toolsets (CLI + messaging platforms)