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/MessageList.tsx

@@ -506,7 +506,7 @@ interface TurnBlockProps {
     activeStreamingPhase?: StreamPhase | null;
 }
 
-const TurnBlock: React.FC<TurnBlockProps> = ({
+const TurnBlock = React.memo(({
     turn,
     isLastTurn,
     sessionIsWorking,
@@ -522,7 +522,7 @@ const TurnBlock: React.FC<TurnBlockProps> = ({
     onUserAnimationConsumed,
     activeStreamingMessageId,
     activeStreamingPhase,
-}) => {
+}: TurnBlockProps) => {
     const turnUiState = turnUiStates.get(turn.turnId) ?? { isExpanded: defaultActivityExpanded };
     const handleToggleTurnGroup = React.useCallback(() => {
         onToggleTurnGroup(turn.turnId);
@@ -783,7 +783,7 @@ const TurnBlock: React.FC<TurnBlockProps> = ({
     return (
         <TurnItem turn={renderableTurn} stickyUserHeader={stickyUserHeader} renderMessage={renderMessage} />
     );
-};
+});
 
 TurnBlock.displayName = 'TurnBlock';
 
@@ -800,7 +800,7 @@ interface UngroupedMessageRowProps {
     activeStreamingPhase?: StreamPhase | null;
 }
 
-const UngroupedMessageRow: React.FC<UngroupedMessageRowProps> = ({
+const UngroupedMessageRow = React.memo(({
     message,
     previousMessage,
     nextMessage,
@@ -811,7 +811,7 @@ const UngroupedMessageRow: React.FC<UngroupedMessageRowProps> = ({
     onUserAnimationConsumed,
     activeStreamingMessageId,
     activeStreamingPhase,
-}) => {
+}: UngroupedMessageRowProps) => {
     return (
         <MessageRow
             message={message}
@@ -826,7 +826,7 @@ const UngroupedMessageRow: React.FC<UngroupedMessageRowProps> = ({
             activeStreamingPhase={message.info.id === activeStreamingMessageId ? activeStreamingPhase : null}
         />
     );
-};
+});
 
 UngroupedMessageRow.displayName = 'UngroupedMessageRow';
 
@@ -859,7 +859,7 @@ const turnContainsMessageId = (turn: TurnRecord, messageId: string | null | unde
     return turn.assistantMessages.some((assistant) => assistant.info.id === messageId);
 };
 
-const MessageListEntry: React.FC<MessageListEntryProps> = ({
+const MessageListEntry = React.memo(({
     entry,
     onMessageContentChange,
     getAnimationHandlers,
@@ -874,7 +874,7 @@ const MessageListEntry: React.FC<MessageListEntryProps> = ({
     onUserAnimationConsumed,
     activeStreamingMessageId,
     activeStreamingPhase,
-}) => {
+}: MessageListEntryProps) => {
     if (entry.kind === 'ungrouped') {
         return (
             <UngroupedMessageRow
@@ -911,7 +911,7 @@ const MessageListEntry: React.FC<MessageListEntryProps> = ({
             stickyUserHeader={stickyUserHeader}
         />
     );
-};
+});
 
 MessageListEntry.displayName = 'MessageListEntry';