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.

tools/skill_manager_tool.py

@@ -822,75 +822,6 @@ def _remove_file(name: str, file_path: str) -> Dict[str, Any]:
 # Main entry point
 # =============================================================================
 
-# ContextVar bypass: set while replaying an already-approved staged skill write
-# so skill_manage() does not re-gate (and re-stage) it.
-import contextvars as _ctxvars
-_skill_gate_bypass: "_ctxvars.ContextVar[bool]" = _ctxvars.ContextVar(
-    "skill_gate_bypass", default=False
-)
-
-
-def _apply_skill_write_gate(action, name, **payload_kwargs):
-    """Evaluate the skill write gate. Returns a JSON tool-result string when the
-    write should NOT proceed (blocked or staged), or None to perform the real
-    write. Bypassed during approved-pending replay.
-    """
-    if action not in {"create", "edit", "patch", "delete", "write_file", "remove_file"}:
-        return None
-    if _skill_gate_bypass.get():
-        return None
-
-    try:
-        from tools import write_approval as wa
-    except Exception:
-        return None  # fail open
-
-    decision = wa.evaluate_gate(wa.SKILLS)
-    if decision.allow:
-        return None
-    if decision.blocked:
-        return tool_error(decision.message, success=False)
-
-    # stage — record the full skill_manage kwargs so approval can replay it.
-    payload = {"action": action, "name": name}
-    payload.update({k: v for k, v in payload_kwargs.items() if v is not None})
-    gist = wa.skill_gist(
-        action, name,
-        content=payload_kwargs.get("content") or "",
-        file_path=payload_kwargs.get("file_path") or "",
-        old_string=payload_kwargs.get("old_string") or "",
-        new_string=payload_kwargs.get("new_string") or "",
-    )
-    record = wa.stage_write(wa.SKILLS, payload, summary=gist, origin=wa.current_origin())
-    return json.dumps(
-        {"success": True, "staged": True, "pending_id": record["id"],
-         "gist": gist, "message": decision.message},
-        ensure_ascii=False,
-    )
-
-
-def apply_skill_pending(payload: Dict[str, Any]) -> str:
-    """Replay a staged skill write, bypassing the gate. Returns the tool result
-    JSON string. Called by the /skills approve handler.
-    """
-    token = _skill_gate_bypass.set(True)
-    try:
-        return skill_manage(
-            action=payload.get("action", ""),
-            name=payload.get("name", ""),
-            content=payload.get("content"),
-            category=payload.get("category"),
-            file_path=payload.get("file_path"),
-            file_content=payload.get("file_content"),
-            old_string=payload.get("old_string"),
-            new_string=payload.get("new_string"),
-            replace_all=payload.get("replace_all", False),
-            absorbed_into=payload.get("absorbed_into"),
-        )
-    finally:
-        _skill_gate_bypass.reset(token)
-
-
 def skill_manage(
     action: str,
     name: str,
@@ -908,19 +839,6 @@ def skill_manage(
 
     Returns JSON string with results.
     """
-    # Approval gate: when on, stages the write for review (skills are too large
-    # to review inline, so they always stage regardless of origin); when off
-    # (default) passes straight through. The gate is bypassed when this call is
-    # itself replaying an already-approved staged write (_skill_apply_pending).
-    gate_result = _apply_skill_write_gate(
-        action, name, content=content, category=category,
-        file_path=file_path, file_content=file_content,
-        old_string=old_string, new_string=new_string,
-        replace_all=replace_all, absorbed_into=absorbed_into,
-    )
-    if gate_result is not None:
-        return gate_result
-
     if action == "create":
         if not content:
             return tool_error("content is required for 'create'. Provide the full SKILL.md text (frontmatter + body).", success=False)