feat(redaction): update to embedPDF v2.4.0 with unified redaction mode support (#5652)

# Description of Changes


Bump to EmbedPDF v2.4.0 plus update to the redaction methods


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Please provide a summary of the changes, including:

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

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---

## Checklist

### General

- [X] I have read the [Contribution
Guidelines](https://github.com/Stirling-Tools/Stirling-PDF/blob/main/CONTRIBUTING.md)
- [X] 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)
- [X] I have performed a self-review of my own code
- [X] 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)

### Translations (if applicable)

- [ ] I ran
[`scripts/counter_translation.py`](https://github.com/Stirling-Tools/Stirling-PDF/blob/main/docs/counter_translation.md)

### 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)

- [X] 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.

---------

Signed-off-by: Balázs Szücs <[email protected]>

frontend/src/core/components/tools/redact/ManualRedactionControls.tsx

@@ -14,51 +14,45 @@ interface ManualRedactionControlsProps {
 /**
  * ManualRedactionControls provides UI for manual PDF redaction in the tool panel.
  * Displays controls for marking text/areas for redaction and applying them.
- * Uses our RedactionContext which bridges to the EmbedPDF API.
  */
 export default function ManualRedactionControls({ disabled = false }: ManualRedactionControlsProps) {
   const { t } = useTranslation();
 
   // Use our RedactionContext which bridges to EmbedPDF
   const { activateTextSelection, activateMarquee, redactionsApplied, setActiveType } = useRedaction();
-  const { pendingCount, activeType, isRedacting, isBridgeReady } = useRedactionMode();
-  
+  const { pendingCount, activeType, isBridgeReady } = useRedactionMode();
+
   // Get viewer context to manage annotation mode and save changes
   const { isAnnotationMode, setAnnotationMode, applyChanges, activeFileIndex } = useViewer();
-  
+
   // Get signature context to deactivate annotation tools when switching to redaction
   const { signatureApiRef } = useSignature();
-  
+
   // Check which tool is active based on activeType
   const isSelectionActive = activeType === 'redactSelection';
   const isMarqueeActive = activeType === 'marqueeRedact';
-  
-  // Track if we've auto-activated
+
+  // Track if we've auto-activated for the current bridge session
   const hasAutoActivated = useRef(false);
-  
+
   // Track the previous file index to detect file switches
   const prevFileIndexRef = useRef<number>(activeFileIndex);
-  
-  // Track previous pending count to detect when all redactions are applied
-  const prevPendingCountRef = useRef<number>(pendingCount);
-  
-  // Track if we're currently auto-saving to prevent re-entry
-  const isAutoSavingRef = useRef(false);
 
   // Auto-activate selection mode when the API bridge becomes ready
-  // This ensures at least one tool is selected when entering manual redaction mode
+  // This ensures Mark Text is pre-selected when entering manual redaction mode
   useEffect(() => {
-    if (isBridgeReady && !disabled && !isRedacting && !hasAutoActivated.current) {
+    if (isBridgeReady && !disabled && !hasAutoActivated.current) {
       hasAutoActivated.current = true;
       // Small delay to ensure EmbedPDF is fully ready
       const timer = setTimeout(() => {
         // Deactivate annotation mode to show redaction layer
         setAnnotationMode(false);
+        // Pre-select the Mark Text tool
         activateTextSelection();
-      }, 100);
+      }, 150);
       return () => clearTimeout(timer);
     }
-  }, [isBridgeReady, disabled, isRedacting, activateTextSelection, setAnnotationMode]);
+  }, [isBridgeReady, disabled, activateTextSelection, setAnnotationMode]);
 
   // Reset auto-activation flag when disabled changes or bridge becomes not ready
   useEffect(() => {
@@ -72,50 +66,19 @@ export default function ManualRedactionControls({ disabled = false }: ManualReda
   useEffect(() => {
     if (prevFileIndexRef.current !== activeFileIndex) {
       prevFileIndexRef.current = activeFileIndex;
-      
+
       // Reset active type to null when switching files
       // This makes both buttons appear unselected, requiring the user to re-click
       // which ensures proper activation on the new PDF
       if (isSelectionActive || isMarqueeActive) {
         setActiveType(null);
       }
+
+      // Reset auto-activation flag so new file can auto-activate
+      hasAutoActivated.current = false;
     }
   }, [activeFileIndex, isSelectionActive, isMarqueeActive, setActiveType]);
 
-  // Auto-save when all pending redactions have been applied
-  // This triggers when the user clicks "Apply (permanent)" on the last pending redaction
-  useEffect(() => {
-    const hadPendingBefore = prevPendingCountRef.current > 0;
-    const hasNoPendingNow = pendingCount === 0;
-    const wasJustCleared = hadPendingBefore && hasNoPendingNow;
-    
-    // Update the ref for next comparison
-    prevPendingCountRef.current = pendingCount;
-    
-    // Auto-save when:
-    // - pendingCount just went from > 0 to 0 (user applied the last pending redaction)
-    // - redactionsApplied is true (at least one redaction was committed)
-    // - not already auto-saving
-    // - applyChanges is available
-    if (wasJustCleared && redactionsApplied && !isAutoSavingRef.current && applyChanges) {
-      isAutoSavingRef.current = true;
-      
-      // Small delay to ensure UI updates before save
-      const timer = setTimeout(async () => {
-        try {
-          await applyChanges();
-        } finally {
-          isAutoSavingRef.current = false;
-        }
-      }, 100);
-      
-      return () => {
-        clearTimeout(timer);
-        isAutoSavingRef.current = false;
-      };
-    }
-  }, [pendingCount, redactionsApplied, applyChanges]);
-
   const handleSelectionClick = () => {
     // Deactivate annotation mode and tools to switch to redaction layer
     if (isAnnotationMode) {
@@ -129,7 +92,7 @@ export default function ManualRedactionControls({ disabled = false }: ManualReda
         }
       }
     }
-    
+
     if (isSelectionActive && !isAnnotationMode) {
       // If already active and not coming from annotation mode, switch to marquee
       activateMarquee();
@@ -151,7 +114,7 @@ export default function ManualRedactionControls({ disabled = false }: ManualReda
         }
       }
     }
-    
+
     if (isMarqueeActive && !isAnnotationMode) {
       // If already active and not coming from annotation mode, switch to selection
       activateTextSelection();
@@ -170,7 +133,7 @@ export default function ManualRedactionControls({ disabled = false }: ManualReda
   // Check if there are unsaved changes to save (pending redactions OR applied redactions)
   // Save Changes button will apply pending redactions and then save everything
   const hasUnsavedChanges = pendingCount > 0 || redactionsApplied;
-  
+
   // Check if API is available - use isBridgeReady state instead of ref (refs don't trigger re-renders)
   const isApiReady = isBridgeReady;
 
@@ -181,7 +144,7 @@ export default function ManualRedactionControls({ disabled = false }: ManualReda
         <Text size="sm" fw={500}>
           {t('redact.manual.title', 'Redaction Tools')}
         </Text>
-        
+
         <Text size="xs" c="dimmed">
           {t('redact.manual.instructions', 'Select text or draw areas on the PDF to mark content for redaction.')}
         </Text>
@@ -196,7 +159,7 @@ export default function ManualRedactionControls({ disabled = false }: ManualReda
             disabled={disabled || !isApiReady}
             size="sm"
             styles={{
-              root: { 
+              root: {
                 minWidth: 0,
               },
               label: { overflow: 'hidden', textOverflow: 'ellipsis', whiteSpace: 'nowrap' },
@@ -214,7 +177,7 @@ export default function ManualRedactionControls({ disabled = false }: ManualReda
             disabled={disabled || !isApiReady}
             size="sm"
             styles={{
-              root: { 
+              root: {
                 minWidth: 0,
               },
               label: { overflow: 'hidden', textOverflow: 'ellipsis', whiteSpace: 'nowrap' },