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.

agent/agent_runtime_helpers.py

@@ -49,7 +49,7 @@ def _ra():
 
 
 AGENT_RUNTIME_POST_HOOK_TOOL_NAMES = frozenset(
-    {"todo", "session_search", "memory", "clarify", "read_terminal", "delegate_task"}
+    {"todo", "session_search", "memory", "clarify", "delegate_task"}
 )
 
 
@@ -679,28 +679,15 @@ def recover_with_credential_pool(
         # long-running TUI sessions stuck on stale tokens until the user
         # exited and reopened.
         is_entitlement = agent._is_entitlement_failure(error_context, status_code)
-        _auth_haystack = " ".join(
-            str(error_context.get(k) or "").lower()
-            for k in ("message", "reason", "code", "error")
-            if isinstance(error_context, dict)
-        )
-        if (
-            not is_entitlement
-            and status_code == 403
-            and "oauth authentication is currently not allowed for this organization" in _auth_haystack
-        ):
-            is_entitlement = True
-        if (
-            not is_entitlement
-            and status_code == 403
-            and (agent.provider or "") == "anthropic"
-            and getattr(agent, "api_mode", "") == "anthropic_messages"
-        ):
-            is_entitlement = True
         if not is_entitlement and status_code == 403 and (agent.provider or "") == "xai-oauth":
+            _disambiguator_haystack = " ".join(
+                str(error_context.get(k) or "").lower()
+                for k in ("message", "reason", "code", "error")
+                if isinstance(error_context, dict)
+            )
             _is_xai_auth_failure = (
-                "[wke=unauthenticated:" in _auth_haystack
-                or "oauth2 access token could not be validated" in _auth_haystack
+                "[wke=unauthenticated:" in _disambiguator_haystack
+                or "oauth2 access token could not be validated" in _disambiguator_haystack
             )
             if not _is_xai_auth_failure:
                 is_entitlement = True
@@ -1797,17 +1784,6 @@ def invoke_tool(agent, function_name: str, function_args: dict, effective_task_i
                 ),
                 next_args,
             )
-    elif function_name == "read_terminal":
-        def _execute(next_args: dict) -> Any:
-            from tools.read_terminal_tool import read_terminal_tool as _read_terminal_tool
-            return _finish_agent_tool(
-                _read_terminal_tool(
-                    start_line=next_args.get("start_line"),
-                    count=next_args.get("count"),
-                    callback=getattr(agent, "read_terminal_callback", None),
-                ),
-                next_args,
-            )
     elif function_name == "delegate_task":
         def _execute(next_args: dict) -> Any:
             return _finish_agent_tool(agent._dispatch_delegate_task(next_args), next_args)