perf: reduce re-renders, fix mobile keyboard handling, add chunk load recovery, and improve PATH management (#1028)

* fix: exclude file content from reverted prompt text

Revert and fork now restore only the user's original prompt, not server-injected file content
Uses existing isSyntheticPart helper for type-safe filtering

* fix: keep scrollbar visible when hovering over thumb

* fix: prevent ESC abort from triggering when terminal is focused

* fix: pass directory to permission/question reply calls so approvals actually resolve

* fix: default model selection not responding after Base UI migration

* fix: prevent modal content from shifting and clipping footer buttons

* fix: improve session switching performance and add sub-agent export with prompt collapse

Defer viewport anchor saving to eliminate ~800ms UI freeze when switching sessions
Add export dialog to include sub-agent tasks recursively in markdown export
Add collapse chevron button for expanded user prompts in sticky header

* fix: resolve sidebar scroll and TDZ crash in session sidebar

* perf: reduce CPU overhead and re-renders across chat, layout, and settings

* fix: position collapse button at top of message and prevent ESC abort in terminal

* fix: position collapse button at top and add padding only when expanded

* refactor: extract shared PATH utilities and mobile keyboard hook

* refactor: import shared path-utils in electron, use module-level style constants

- Electron now imports pathLooksUserConfigured/mergePathValues from
  shared path-utils.js instead of inline duplication
- ToolPart collapsedCustomStyle moved from useMemo([]) to module const

* fix: resolve remaining merge conflicts and type errors

- Remove duplicate variable declarations in SessionNodeItem
- Remove orphaned export callback body from conflict resolution
- Fix HelpDialog description -> descriptionKey (i18n rename)

* fix: resolve type-check and lint errors in session-actions.test.ts

- Added missing bun:test type declarations (beforeEach, mock, mock.module)
- Removed unused State import
- Replaced 'as any' casts with proper OpencodeClient and ChildStoreManager types
- Added eslint-disable for unused _ parameter in mock function

* fix PR 1028 export and PATH edge cases

* fix startup retry exhaustion state

* remove opencode package lock change

* fix sub-session rename cancellation

---------

Co-authored-by: Bohdan Triapitsyn <artmore@protonmail.com>

packages/ui/src/components/chat/message/MessageBody.tsx

@@ -44,6 +44,9 @@ import { useEffectiveDirectory } from '@/hooks/useEffectiveDirectory';
 import { useSessions } from '@/sync/sync-context';
 import { useI18n } from '@/lib/i18n';
 
+const CONTAIN_LAYOUT_STYLE = { contain: 'layout' as const, transform: 'translateZ(0)' };
+const MESSAGE_FOOTER_CONTAINER_STYLE = { containerType: 'inline-size' as const, containerName: 'message-footer' };
+
 type SubtaskPartLike = Part & {
     type: 'subtask';
     description?: unknown;
@@ -320,7 +323,7 @@ const writeRevealedToolIds = (messageId: string, value: Set<string>): void => {
     revealedToolIdsByMessage.set(messageId, new Set(value));
 };
 
-const UserMessageBody: React.FC<{
+const UserMessageBody = React.memo(({ messageId, parts, isMobile, hasTouchInput, hasTextContent, onCopyMessage, copiedMessage, onShowPopup, agentMention, onRevert, onFork, userActionsMode = 'inline', stickyUserHeaderEnabled = true }: {
     messageId: string;
     parts: Part[];
     isMobile: boolean;
@@ -334,7 +337,7 @@ const UserMessageBody: React.FC<{
     onFork?: () => void;
     userActionsMode?: 'inline' | 'external-content' | 'external-actions';
     stickyUserHeaderEnabled?: boolean;
-}> = ({ messageId, parts, isMobile, hasTouchInput, hasTextContent, onCopyMessage, copiedMessage, onShowPopup, agentMention, onRevert, onFork, userActionsMode = 'inline', stickyUserHeaderEnabled = true }) => {
+}) => {
     const { t } = useI18n();
     const [copyHintVisible, setCopyHintVisible] = React.useState(false);
     const copyHintTimeoutRef = React.useRef<number | null>(null);
@@ -519,7 +522,7 @@ const UserMessageBody: React.FC<{
     return (
         <div
             className="relative w-full group/message"
-            style={{ contain: 'layout', transform: 'translateZ(0)' }}
+            style={CONTAIN_LAYOUT_STYLE}
             onTouchStart={isTouchContext && canCopyMessage && hasCopyableText ? revealCopyHint : undefined}
         >
             <div
@@ -572,9 +575,9 @@ const UserMessageBody: React.FC<{
             {actionsBlock}
         </div>
     );
-};
+});
 
-const AssistantMessageBody: React.FC<Omit<MessageBodyProps, 'isUser'>> = ({
+const AssistantMessageBody = React.memo(({
     sessionId,
     messageId,
     parts,
@@ -599,7 +602,7 @@ const AssistantMessageBody: React.FC<Omit<MessageBodyProps, 'isUser'>> = ({
     showReasoningTraces = false,
     turnGroupingContext,
     errorMessage,
-}) => {
+}: Omit<MessageBodyProps, 'isUser'>) => {
     const { t } = useI18n();
     const streamPhase = _streamPhase;
     void _allowAnimation;
@@ -1564,13 +1567,10 @@ const AssistantMessageBody: React.FC<Omit<MessageBodyProps, 'isUser'>> = ({
              className={cn(
                  'relative w-full group/message'
              )}
-             style={{
-                 contain: 'layout',
-                 transform: 'translateZ(0)',
-             }}
-             onTouchStart={isTouchContext && canCopyMessage && hasCopyableText ? revealCopyHint : undefined}
-         >
-             <TextSelectionMenu containerRef={messageContentRef} />
+              style={CONTAIN_LAYOUT_STYLE}
+              onTouchStart={isTouchContext && canCopyMessage && hasCopyableText ? revealCopyHint : undefined}
+          >
+              <TextSelectionMenu containerRef={messageContentRef} />
              <SaveProjectPlanDialog
                  open={isPlanDialogOpen}
                  onOpenChange={setIsPlanDialogOpen}
@@ -1601,7 +1601,7 @@ const AssistantMessageBody: React.FC<Omit<MessageBodyProps, 'isUser'>> = ({
                 {shouldShowFooter && (
                     <div
                         className="mt-2 mb-1 flex items-center justify-start gap-1.5"
-                        style={{ containerType: 'inline-size', containerName: 'message-footer' }}
+                        style={MESSAGE_FOOTER_CONTAINER_STYLE}
                     >
                         <div className="flex items-center gap-1.5">
                             {footerButtons}
@@ -1642,9 +1642,9 @@ const AssistantMessageBody: React.FC<Omit<MessageBodyProps, 'isUser'>> = ({
             </div>
         </div>
     );
-};
+});
 
-const MessageBody: React.FC<MessageBodyProps> = ({ isUser, ...props }) => {
+const MessageBody = React.memo(({ isUser, ...props }: MessageBodyProps) => {
 
     if (isUser) {
         return (
@@ -1667,6 +1667,6 @@ const MessageBody: React.FC<MessageBodyProps> = ({ isUser, ...props }) => {
     }
 
     return <AssistantMessageBody {...props} />;
-};
+});
 
 export default MessageBody;