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/ModelControls.tsx

@@ -2057,20 +2057,20 @@ export const ModelControls: React.FC<ModelControlsProps> = ({
         );
     };
 
-    // Filter models based on search query
-    const filterByQuery = (modelName: string, providerName: string, query: string) => {
-        if (!query.trim()) return true;
-        return (
-            matchesModelSearch(modelName, query) ||
-            matchesModelSearch(providerName, query)
-        );
-    };
+    type FlatModelItem = { model: ProviderModel; providerID: string; modelID: string; section: string };
+
+    const modelSelectorData = React.useMemo(() => {
+        const filterByQuery = (modelName: string, providerName: string, query: string) => {
+            if (!query.trim()) return true;
+            return (
+                matchesModelSearch(modelName, query) ||
+                matchesModelSearch(providerName, query)
+            );
+        };
 
-    const renderModelSelector = () => {
         const normalizedDesktopQuery = desktopModelQuery.trim();
         const forceExpandProviders = normalizedDesktopQuery.length > 0;
 
-        // Filter favorites
         const filteredFavorites = favoriteModelsList.filter(({ model, providerID }) => {
             const provider = providers.find(p => p.id === providerID);
             const providerName = provider?.name || providerID;
@@ -2078,7 +2078,6 @@ export const ModelControls: React.FC<ModelControlsProps> = ({
             return filterByQuery(modelName, providerName, desktopModelQuery);
         });
 
-        // Filter recents
         const filteredRecents = recentModelsList.filter(({ model, providerID }) => {
             const provider = providers.find(p => p.id === providerID);
             const providerName = provider?.name || providerID;
@@ -2086,7 +2085,6 @@ export const ModelControls: React.FC<ModelControlsProps> = ({
             return filterByQuery(modelName, providerName, desktopModelQuery);
         });
 
-        // Filter providers and their models
         const filteredProviders = visibleProviders
             .map((provider) => {
                 const providerModels = Array.isArray(provider.models) ? provider.models : [];
@@ -2115,8 +2113,6 @@ export const ModelControls: React.FC<ModelControlsProps> = ({
             filteredRecents.length > 0 ||
             filteredProviders.length > 0;
 
-        // Build flat list for keyboard navigation
-        type FlatModelItem = { model: ProviderModel; providerID: string; modelID: string; section: string };
         const flatModelList: FlatModelItem[] = [];
 
         filteredFavorites.forEach(({ model, providerID, modelID }) => {
@@ -2131,6 +2127,12 @@ export const ModelControls: React.FC<ModelControlsProps> = ({
             });
         });
 
+        return { filteredFavorites, filteredRecents, filteredProviders, providerSections, flatModelList, hasResults, forceExpandProviders };
+    }, [desktopModelQuery, favoriteModelsList, recentModelsList, visibleProviders, providers, collapsedProviderSet, matchesModelSearch]);
+
+    const renderModelSelector = () => {
+        const { filteredFavorites, filteredRecents, filteredProviders, providerSections, flatModelList, hasResults, forceExpandProviders } = modelSelectorData;
+
         const totalItems = flatModelList.length;
 
         // Check if currently highlighted model supports thinking variants