feat(tui): find bundled entry.js from wheel before falling back to npm build

Add _find_bundled_tui() that checks for hermes_cli/tui_dist/entry.js
(present in wheel installs) and wire it into _make_tui_argv() between
the HERMES_TUI_DIR prebuilt path and the npm install fallback.

tests/hermes_cli/test_tui_bundled.py

@@ -0,0 +1,21 @@
+from pathlib import Path
+
+
+def test_tui_finds_bundled_entry_js(tmp_path):
+    """_find_bundled_tui finds entry.js bundled in the package."""
+    tui_dist = tmp_path / "hermes_cli" / "tui_dist"
+    tui_dist.mkdir(parents=True)
+    entry = tui_dist / "entry.js"
+    entry.write_text("// bundled TUI", encoding="utf-8")
+
+    from hermes_cli.main import _find_bundled_tui
+    result = _find_bundled_tui(hermes_cli_dir=tmp_path / "hermes_cli")
+    assert result is not None
+    assert result.name == "entry.js"
+
+
+def test_tui_returns_none_when_no_bundle(tmp_path):
+    """_find_bundled_tui returns None when no bundle exists."""
+    from hermes_cli.main import _find_bundled_tui
+    result = _find_bundled_tui(hermes_cli_dir=tmp_path / "hermes_cli")
+    assert result is None