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.

hermes_cli/model_catalog.py

@@ -356,37 +356,6 @@ def get_curated_nous_models() -> list[str] | None:
     return out or None
 
 
-def seed_cache_from_checkout(project_root: "Path | str") -> bool:
-    """Overwrite the disk cache with the catalog shipped in a local checkout.
-
-    ``hermes update`` pulls the latest repo, so the freshly-pulled
-    ``website/static/api/model-catalog.json`` IS the newest catalog — no
-    network round-trip needed. Copying it straight over the disk cache keeps
-    the model picker current even when the remote manifest fetch is bot-gated
-    or the Portal hiccups.
-
-    Reads the shipped manifest, validates it against the schema, and writes it
-    to ``~/.hermes/cache/model_catalog.json`` via the same atomic writer the
-    network path uses. Returns ``True`` on success, ``False`` if the file is
-    missing, malformed, or fails validation (caller should treat a ``False``
-    as non-fatal — the network fetch path still applies on the next picker
-    open).
-    """
-    src = Path(project_root) / "website" / "static" / "api" / "model-catalog.json"
-    try:
-        with open(src, encoding="utf-8") as fh:
-            data = json.load(fh)
-    except (OSError, json.JSONDecodeError) as exc:
-        logger.debug("model catalog seed from checkout skipped (%s): %s", src, exc)
-        return False
-    if not _validate_manifest(data):
-        logger.debug("model catalog seed from checkout skipped: invalid manifest at %s", src)
-        return False
-    _write_disk_cache(data)
-    reset_cache()  # drop the in-process copy so the next read picks up the seed
-    return True
-
-
 def reset_cache() -> None:
     """Clear the in-process cache. Used by tests and ``hermes model --refresh``."""
     global _catalog_cache, _catalog_cache_source_mtime