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/FileAttachment.tsx

@@ -522,7 +522,7 @@ export const MessageFilesDisplay = memo(({ files, onShowPopup, compact = false }
         if (isImage && file.url) {
           return (
             <div
-              key={index}
+              key={file.url || `${fileName}-${index}`}
               className="relative aspect-video rounded-lg border border-border/40 bg-muted/10 overflow-hidden group"
             >
               <img
@@ -542,7 +542,7 @@ export const MessageFilesDisplay = memo(({ files, onShowPopup, compact = false }
 
         if (githubLinkKind && file.url) {
           return (
-            <Tooltip key={index}>
+            <Tooltip key={file.url || `${fileName}-${index}`}>
               <TooltipTrigger asChild>
                 <button
                   type="button"
@@ -575,7 +575,7 @@ export const MessageFilesDisplay = memo(({ files, onShowPopup, compact = false }
         }
 
         return (
-          <Tooltip key={index}>
+          <Tooltip key={file.url || `${fileName}-${index}`}>
             <TooltipTrigger asChild>
               <button
                 type="button"
@@ -646,7 +646,7 @@ export const ImageGallery = memo(({ urls, caption, onShowPopup }: ImageGalleryPr
       <div className={cn("grid gap-2", getGridCols())}>
         {urls.map((url, index) => (
           <button
-            key={index}
+            key={url}
             type="button"
             onClick={() => onShowPopup?.({
               open: true,