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/send_message_tool.py

@@ -38,7 +38,7 @@ _NUMERIC_TOPIC_RE = _TELEGRAM_TOPIC_TARGET_RE
 # below and falls through to channel-name resolution, which has no way to
 # resolve a raw phone number. Keeping the '+' preserves the E.164 form that
 # downstream adapters (signal, etc.) expect.
-_PHONE_PLATFORMS = frozenset({"photon", "signal", "sms", "whatsapp"})
+_PHONE_PLATFORMS = frozenset({"signal", "sms", "whatsapp"})
 _E164_TARGET_RE = re.compile(r"^\s*\+(\d{7,15})\s*$")
 # Email addresses — a valid email like "user@domain.com" should be treated as
 # an explicit target for the email platform, not fall through to channel-name