fix(mobile): move native-chat latest-value ref writes out of render

Render-time ref writes can leak from discarded render work (react-freeze
makes discarded renders reachable on mobile) and fail the blocking
React Doctor changed-lines CI gate. Use the layout-effect idiom already
established in use-mobile-native-chat-active-resolution.

Claude-Session: https://claude.ai/code/session_01CNFkBiVT51tM6UA5i2rcaK

mobile/src/session/use-mobile-native-chat-image-upload.ts

@@ -1,4 +1,4 @@
-import { useCallback, useRef, useState } from 'react'
+import { useCallback, useLayoutEffect, useRef, useState } from 'react'
 import { CLIPBOARD_IMAGE_TOO_LARGE_ERROR } from '../../../src/shared/clipboard-image'
 import type { RpcClient } from '../transport/rpc-client'
 import type { ConnectionState } from '../transport/types'
@@ -46,7 +46,9 @@ export function useMobileNativeChatImageUpload(args: {
   const [isAttaching, setIsAttaching] = useState(false)
   const attachingCount = useRef(0)
   const connStateRef = useRef(connState)
-  connStateRef.current = connState
+  useLayoutEffect(() => {
+    connStateRef.current = connState
+  }, [connState])
 
   const attachImage = useCallback(
     async (source: MobileImageSource): Promise<void> => {

mobile/src/session/use-mobile-structured-agent-state.ts

@@ -1,4 +1,4 @@
-import { useCallback, useEffect, useRef, useState } from 'react'
+import { useCallback, useEffect, useLayoutEffect, useRef, useState } from 'react'
 import type {
   AgentSessionHistoryResult,
   AgentSessionSubscribeEvent
@@ -37,7 +37,9 @@ export function useMobileStructuredAgentState(args: {
   const [state, setState] = useState<StructuredAgentSessionState>(EMPTY_STRUCTURED_AGENT_SESSION)
   const [loadingOlder, setLoadingOlder] = useState(false)
   const stateRef = useRef(state)
-  stateRef.current = state
+  useLayoutEffect(() => {
+    stateRef.current = state
+  }, [state])
 
   const apply = useCallback((action: StructuredAgentSessionAction) => {
     setState((current) => reduceStructuredAgentSession(current, action))