legacy UI (#4612)

# Description of Changes

<!--
Please provide a summary of the changes, including:

- What was changed
- Why the change was made
- Any challenges encountered

Closes #(issue_number)
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---

## Checklist

### General

- [ ] I have read the [Contribution
Guidelines](https://github.com/Stirling-Tools/Stirling-PDF/blob/main/CONTRIBUTING.md)
- [ ] I have read the [Stirling-PDF Developer
Guide](https://github.com/Stirling-Tools/Stirling-PDF/blob/main/devGuide/DeveloperGuide.md)
(if applicable)
- [ ] I have read the [How to add new languages to
Stirling-PDF](https://github.com/Stirling-Tools/Stirling-PDF/blob/main/devGuide/HowToAddNewLanguage.md)
(if applicable)
- [ ] I have performed a self-review of my own code
- [ ] My changes generate no new warnings

### Documentation

- [ ] I have updated relevant docs on [Stirling-PDF's doc
repo](https://github.com/Stirling-Tools/Stirling-Tools.github.io/blob/main/docs/)
(if functionality has heavily changed)
- [ ] I have read the section [Add New Translation
Tags](https://github.com/Stirling-Tools/Stirling-PDF/blob/main/devGuide/HowToAddNewLanguage.md#add-new-translation-tags)
(for new translation tags only)

### UI Changes (if applicable)

- [ ] Screenshots or videos demonstrating the UI changes are attached
(e.g., as comments or direct attachments in the PR)

### Testing (if applicable)

- [ ] I have tested my changes locally. Refer to the [Testing
Guide](https://github.com/Stirling-Tools/Stirling-PDF/blob/main/devGuide/DeveloperGuide.md#6-testing)
for more details.

---------

Co-authored-by: Claude <[email protected]>
Co-authored-by: EthanHealy01 <[email protected]>
Co-authored-by: EthanHealy01 <[email protected]>

frontend/src/contexts/toolWorkflow/toolWorkflowState.ts

@@ -0,0 +1,88 @@
+import { PageEditorFunctions } from '../../types/pageEditor';
+
+// State & Modes
+export type ToolPanelMode = 'sidebar' | 'fullscreen';
+
+export interface ToolWorkflowState {
+  // UI State
+  sidebarsVisible: boolean;
+  leftPanelView: 'toolPicker' | 'toolContent' | 'hidden';
+  readerMode: boolean;
+  toolPanelMode: ToolPanelMode;
+
+  previewFile: File | null;
+  pageEditorFunctions: PageEditorFunctions | null;
+
+  // Search State
+  searchQuery: string;
+}
+
+// Actions
+export type ToolWorkflowAction =
+  | { type: 'SET_SIDEBARS_VISIBLE'; payload: boolean }
+  | { type: 'SET_LEFT_PANEL_VIEW'; payload: 'toolPicker' | 'toolContent' | 'hidden' }
+  | { type: 'SET_READER_MODE'; payload: boolean }
+  | { type: 'SET_TOOL_PANEL_MODE'; payload: ToolPanelMode }
+  | { type: 'SET_PREVIEW_FILE'; payload: File | null }
+  | { type: 'SET_PAGE_EDITOR_FUNCTIONS'; payload: PageEditorFunctions | null }
+  | { type: 'SET_SEARCH_QUERY'; payload: string }
+  | { type: 'RESET_UI_STATE' };
+
+// Storage keys
+export const TOOL_PANEL_MODE_STORAGE_KEY = 'toolPanelModePreference';
+
+export const getStoredToolPanelMode = (): ToolPanelMode => {
+  if (typeof window === 'undefined') {
+    return 'sidebar';
+  }
+
+  const stored = window.localStorage.getItem(TOOL_PANEL_MODE_STORAGE_KEY);
+  if (stored === 'fullscreen') {
+    return 'fullscreen';
+  }
+
+  return 'sidebar';
+};
+
+export const baseState: Omit<ToolWorkflowState, 'toolPanelMode'> = {
+  sidebarsVisible: true,
+  leftPanelView: 'toolPicker',
+  readerMode: false,
+  previewFile: null,
+  pageEditorFunctions: null,
+  searchQuery: '',
+};
+
+export const createInitialState = (): ToolWorkflowState => ({
+  ...baseState,
+  toolPanelMode: getStoredToolPanelMode(),
+});
+
+export function toolWorkflowReducer(state: ToolWorkflowState, action: ToolWorkflowAction): ToolWorkflowState {
+  switch (action.type) {
+    case 'SET_SIDEBARS_VISIBLE':
+      return { ...state, sidebarsVisible: action.payload };
+    case 'SET_LEFT_PANEL_VIEW':
+      return { ...state, leftPanelView: action.payload };
+    case 'SET_READER_MODE':
+      return { ...state, readerMode: action.payload };
+    case 'SET_TOOL_PANEL_MODE':
+      return { ...state, toolPanelMode: action.payload };
+    case 'SET_PREVIEW_FILE':
+      return { ...state, previewFile: action.payload };
+    case 'SET_PAGE_EDITOR_FUNCTIONS':
+      return { ...state, pageEditorFunctions: action.payload };
+    case 'SET_SEARCH_QUERY':
+      return { ...state, searchQuery: action.payload };
+    case 'RESET_UI_STATE':
+      return {
+        ...baseState,
+        toolPanelMode: state.toolPanelMode,
+        searchQuery: state.searchQuery,
+      };
+    default:
+      return state;
+  }
+}
+
+