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.

apps/desktop/electron/workspace-cwd.cjs

@@ -1,38 +0,0 @@
-const path = require('node:path')
-
-/** True when `dir` lives inside a packaged app bundle / install tree. */
-function isPackagedInstallPath(dir, { installRoots, isPackaged }) {
-  if (!isPackaged || !dir) {
-    return false
-  }
-
-  let resolved
-
-  try {
-    resolved = path.resolve(String(dir))
-  } catch {
-    return false
-  }
-
-  const roots = new Set(
-    (installRoots ?? [])
-      .filter(Boolean)
-      .map(candidate => path.resolve(String(candidate)))
-  )
-
-  for (const root of roots) {
-    if (resolved === root) {
-      return true
-    }
-
-    const rel = path.relative(root, resolved)
-
-    if (rel && !rel.startsWith('..') && !path.isAbsolute(rel)) {
-      return true
-    }
-  }
-
-  return false
-}
-
-module.exports = { isPackagedInstallPath }