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/preload.cjs

@@ -5,7 +5,6 @@ contextBridge.exposeInMainWorld('hermesDesktop', {
   revalidateConnection: () => ipcRenderer.invoke('hermes:connection:revalidate'),
   touchBackend: profile => ipcRenderer.invoke('hermes:backend:touch', profile),
   getGatewayWsUrl: profile => ipcRenderer.invoke('hermes:gateway:ws-url', profile),
-  openSessionWindow: sessionId => ipcRenderer.invoke('hermes:window:openSession', sessionId),
   getBootProgress: () => ipcRenderer.invoke('hermes:boot-progress:get'),
   getConnectionConfig: profile => ipcRenderer.invoke('hermes:connection-config:get', profile),
   saveConnectionConfig: payload => ipcRenderer.invoke('hermes:connection-config:save', payload),
@@ -42,7 +41,6 @@ contextBridge.exposeInMainWorld('hermesDesktop', {
   setPreviewShortcutActive: active => ipcRenderer.send('hermes:previewShortcutActive', Boolean(active)),
   openExternal: url => ipcRenderer.invoke('hermes:openExternal', url),
   fetchLinkTitle: url => ipcRenderer.invoke('hermes:fetchLinkTitle', url),
-  sanitizeWorkspaceCwd: cwd => ipcRenderer.invoke('hermes:workspace:sanitize', cwd),
   settings: {
     getDefaultProjectDir: () => ipcRenderer.invoke('hermes:setting:defaultProjectDir:get'),
     setDefaultProjectDir: dir => ipcRenderer.invoke('hermes:setting:defaultProjectDir:set', dir),
@@ -80,12 +78,6 @@ contextBridge.exposeInMainWorld('hermesDesktop', {
     ipcRenderer.on('hermes:open-updates', listener)
     return () => ipcRenderer.removeListener('hermes:open-updates', listener)
   },
-  onDeepLink: callback => {
-    const listener = (_event, payload) => callback(payload)
-    ipcRenderer.on('hermes:deep-link', listener)
-    return () => ipcRenderer.removeListener('hermes:deep-link', listener)
-  },
-  signalDeepLinkReady: () => ipcRenderer.invoke('hermes:deep-link-ready'),
   onWindowStateChanged: callback => {
     const listener = (_event, payload) => callback(payload)
     ipcRenderer.on('hermes:window-state-changed', listener)
@@ -140,9 +132,5 @@ contextBridge.exposeInMainWorld('hermesDesktop', {
       ipcRenderer.on('hermes:updates:progress', listener)
       return () => ipcRenderer.removeListener('hermes:updates:progress', listener)
     }
-  },
-  themes: {
-    fetchMarketplace: id => ipcRenderer.invoke('hermes:vscode-theme:fetch', id),
-    searchMarketplace: query => ipcRenderer.invoke('hermes:vscode-theme:search', query)
   }
 })