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/app/session/hooks/use-message-stream.ts

@@ -1,7 +1,6 @@
 import type { QueryClient } from '@tanstack/react-query'
 import { type MutableRefObject, useCallback, useEffect, useRef } from 'react'
 
-import { readActiveTerminal } from '@/app/right-sidebar/terminal/buffer'
 import {
   appendAssistantTextPart,
   appendReasoningPart,
@@ -15,11 +14,9 @@ import {
   upsertToolPart
 } from '@/lib/chat-messages'
 import { coerceGatewayText, coerceThinkingText, normalizePersonalityValue } from '@/lib/chat-runtime'
-import { gatewayEventRequiresSessionId } from '@/lib/gateway-events'
 import { triggerHaptic } from '@/lib/haptics'
 import { isProviderSetupErrorMessage } from '@/lib/provider-setup-errors'
 import { setClarifyRequest } from '@/store/clarify'
-import { $gateway } from '@/store/gateway'
 import { notify } from '@/store/notifications'
 import { requestDesktopOnboarding } from '@/store/onboarding'
 import { clearAllPrompts, setApprovalRequest, setSecretRequest, setSudoRequest } from '@/store/prompts'
@@ -64,67 +61,6 @@ interface QueuedStreamDeltas {
   reasoning: string
 }
 
-type SessionRuntimeStatePatch = Partial<
-  Pick<
-    ClientSessionState,
-    | 'branch'
-    | 'cwd'
-    | 'fast'
-    | 'model'
-    | 'personality'
-    | 'provider'
-    | 'reasoningEffort'
-    | 'serviceTier'
-    | 'yolo'
-  >
->
-
-function sessionInfoStatePatch(payload: GatewayEventPayload | undefined): SessionRuntimeStatePatch {
-  const patch: SessionRuntimeStatePatch = {}
-
-  if (typeof payload?.model === 'string') {
-    patch.model = payload.model || ''
-  }
-
-  if (typeof payload?.provider === 'string') {
-    patch.provider = payload.provider || ''
-  }
-
-  if (typeof payload?.cwd === 'string') {
-    patch.cwd = payload.cwd
-  }
-
-  if (typeof payload?.branch === 'string') {
-    patch.branch = payload.branch
-  }
-
-  if (typeof payload?.personality === 'string') {
-    patch.personality = normalizePersonalityValue(payload.personality)
-  }
-
-  if (typeof payload?.reasoning_effort === 'string') {
-    patch.reasoningEffort = payload.reasoning_effort
-  }
-
-  if (typeof payload?.service_tier === 'string') {
-    patch.serviceTier = payload.service_tier
-  }
-
-  if (typeof payload?.fast === 'boolean') {
-    patch.fast = payload.fast
-  }
-
-  if (typeof payload?.yolo === 'boolean') {
-    patch.yolo = payload.yolo
-  }
-
-  return patch
-}
-
-function hasSessionInfoStatePatch(patch: SessionRuntimeStatePatch): boolean {
-  return Object.keys(patch).length > 0
-}
-
 // Minimum gap between two assistant-text flushes during a stream. Was 16ms
 // (rAF only), which at typical LLM token rates of ~30-80 tok/sec meant every
 // token got its own React commit + Streamdown markdown re-parse, scaling
@@ -677,9 +613,6 @@ export function useMessageStream({
     (event: RpcEvent) => {
       const payload = event.payload as GatewayEventPayload | undefined
       const explicitSid = event.session_id || ''
-      if (!explicitSid && gatewayEventRequiresSessionId(event.type)) {
-        return
-      }
       const sessionId = explicitSid || activeSessionIdRef.current
       const isActiveEvent = !!sessionId && sessionId === activeSessionIdRef.current
 
@@ -689,13 +622,13 @@ export function useMessageStream({
         // Apply session-scoped fields when the event targets the active
         // session, OR when it's a global broadcast and we have no session.
         const apply = explicitSid ? isActiveEvent : !activeSessionIdRef.current
-        const statePatch = sessionInfoStatePatch(payload)
-        const hasStatePatch = hasSessionInfoStatePatch(statePatch)
         const modelChanged = typeof payload?.model === 'string'
         const providerChanged = typeof payload?.provider === 'string'
         const runningChanged = typeof payload?.running === 'boolean'
 
         if (apply) {
+          const runtimeInfo: { branch?: string; cwd?: string } = {}
+
           if (modelChanged) {
             setCurrentModel(payload!.model || '')
           }
@@ -706,10 +639,20 @@ export function useMessageStream({
 
           if (typeof payload?.cwd === 'string') {
             setCurrentCwd(payload.cwd)
+            runtimeInfo.cwd = payload.cwd
           }
 
           if (typeof payload?.branch === 'string') {
             setCurrentBranch(payload.branch)
+            runtimeInfo.branch = payload.branch
+          }
+
+          if (sessionId && (runtimeInfo.cwd !== undefined || runtimeInfo.branch !== undefined)) {
+            updateSessionState(sessionId, state => ({
+              ...state,
+              branch: runtimeInfo.branch ?? state.branch,
+              cwd: runtimeInfo.cwd ?? state.cwd
+            }))
           }
 
           if (typeof payload?.personality === 'string') {
@@ -731,18 +674,7 @@ export function useMessageStream({
           if (typeof payload?.yolo === 'boolean') {
             setYoloActive(payload.yolo)
           }
-        }
 
-        if (sessionId && hasStatePatch) {
-          updateSessionState(sessionId, state => ({
-            ...state,
-            ...statePatch,
-            branch: statePatch.branch ?? state.branch,
-            cwd: statePatch.cwd ?? state.cwd
-          }))
-        }
-
-        if (apply) {
           if (runningChanged && sessionId) {
             updateSessionState(sessionId, state => {
               const busy = Boolean(payload!.running)
@@ -933,8 +865,6 @@ export function useMessageStream({
         // raise it and wait — the sidebar flags "needs input" and the inline bar
         // surfaces once the user focuses that chat.
         setApprovalRequest({
-          // false only when a tirith warning forbids it; backend omits the field otherwise.
-          allowPermanent: payload?.allow_permanent !== false,
           command: typeof payload?.command === 'string' ? payload.command : '',
           description: typeof payload?.description === 'string' ? payload.description : 'dangerous command',
           sessionId: sessionId ?? null
@@ -972,21 +902,6 @@ export function useMessageStream({
             updateSessionState(sessionId, state => ({ ...state, needsInput: true }))
           }
         }
-      } else if (event.type === 'terminal.read.request') {
-        // read_terminal tool: serialize the renderer's xterm buffer and answer
-        // immediately (Python blocks on the respond). Empty text = no live pane.
-        const requestId = typeof payload?.request_id === 'string' ? payload.request_id : ''
-
-        if (requestId) {
-          const start = typeof payload?.start === 'number' ? payload.start : undefined
-          const count = typeof payload?.count === 'number' ? payload.count : undefined
-          const result = readActiveTerminal({ start, count })
-
-          void $gateway.get()?.request('terminal.read.respond', {
-            request_id: requestId,
-            text: result ? JSON.stringify(result) : ''
-          })
-        }
       } else if (event.type === 'error') {
         const errorMessage = payload?.message || 'Hermes reported an error'
         const looksLikeProviderSetup = isProviderSetupErrorMessage(errorMessage)