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/src/hermes.ts

@@ -7,7 +7,6 @@ import type {
   AudioSpeakResponse,
   AudioTranscriptionResponse,
   AuxiliaryModelsResponse,
-  BackendUpdateCheckResponse,
   ConfigSchemaResponse,
   CronJob,
   CronJobCreatePayload,
@@ -57,7 +56,6 @@ export type {
   AudioSpeakResponse,
   AudioTranscriptionResponse,
   AuxiliaryModelsResponse,
-  BackendUpdateCheckResponse,
   ConfigFieldSchema,
   ConfigSchemaResponse,
   CronJob,
@@ -218,7 +216,6 @@ export function getSessionMessages(id: string, profile?: string | null): Promise
   const suffix = profile ? `?profile=${encodeURIComponent(profile)}` : ''
 
   return window.hermesDesktop.api<SessionMessagesResponse>({
-    ...(profile ? { profile } : {}),
     path: `/api/sessions/${encodeURIComponent(id)}/messages${suffix}`
   })
 }
@@ -344,14 +341,13 @@ export function setEnvVar(key: string, value: string): Promise<{ ok: boolean }>
 
 export function validateProviderCredential(
   key: string,
-  value: string,
-  apiKey?: string
+  value: string
 ): Promise<{ ok: boolean; reachable: boolean; message: string; models?: string[] }> {
   return window.hermesDesktop.api<{ ok: boolean; reachable: boolean; message: string; models?: string[] }>({
     ...profileScoped(),
     path: '/api/providers/validate',
     method: 'POST',
-    body: { key, value, api_key: apiKey ?? '' }
+    body: { key, value }
   })
 }
 
@@ -690,15 +686,6 @@ export function updateHermes(): Promise<ActionResponse> {
   })
 }
 
-/** Query the connected backend's own update state. In remote mode this is the
- *  authoritative source for the backend's behind-count + "what's changed",
- *  distinct from the Electron client clone's git state. */
-export function checkHermesUpdate(force = false): Promise<BackendUpdateCheckResponse> {
-  return window.hermesDesktop.api<BackendUpdateCheckResponse>({
-    path: `/api/hermes/update/check${force ? '?force=true' : ''}`
-  })
-}
-
 export function getActionStatus(name: string, lines = 200): Promise<ActionStatusResponse> {
   return window.hermesDesktop.api<ActionStatusResponse>({
     path: `/api/actions/${encodeURIComponent(name)}/status?lines=${Math.max(1, lines)}`