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.

tests/tools/test_send_message_target_parse.py

@@ -1,20 +0,0 @@
-"""Parser-only tests for send_message targets.
-
-These stay separate from ``test_send_message_tool.py`` because that module
-skips wholesale when optional Telegram dependencies are not installed.
-"""
-
-from tools.send_message_tool import _parse_target_ref
-
-
-def test_photon_e164_target_is_explicit() -> None:
-    chat_id, thread_id, is_explicit = _parse_target_ref("photon", "+15551234567")
-
-    assert chat_id == "+15551234567"
-    assert thread_id is None
-    assert is_explicit is True
-
-
-def test_e164_target_still_requires_phone_platform() -> None:
-    assert _parse_target_ref("matrix", "+15551234567")[2] is False
-