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.

skills/github/github-auth/scripts/gh-env.sh

@@ -23,8 +23,8 @@ if command -v gh &>/dev/null && gh auth status &>/dev/null 2>&1; then
     GH_USER=$(gh api user --jq '.login' 2>/dev/null)
 elif [ -n "$GITHUB_TOKEN" ]; then
     GH_AUTH_METHOD="curl"
-elif _hermes_env="${HERMES_HOME:-$HOME/.hermes}/.env"; [ -f "$_hermes_env" ] && grep -q "^GITHUB_TOKEN=" "$_hermes_env" 2>/dev/null; then
-    GITHUB_TOKEN=$(grep "^GITHUB_TOKEN=" "$_hermes_env" | head -1 | cut -d= -f2 | tr -d '\n\r')
+elif [ -f "$HOME/.hermes/.env" ] && grep -q "^GITHUB_TOKEN=" "$HOME/.hermes/.env" 2>/dev/null; then
+    GITHUB_TOKEN=$(grep "^GITHUB_TOKEN=" "$HOME/.hermes/.env" | head -1 | cut -d= -f2 | tr -d '\n\r')
     if [ -n "$GITHUB_TOKEN" ]; then
         GH_AUTH_METHOD="curl"
     fi