feat(rotate,delete-pages): Add custom rotation angles and enhance page management UI

- Add TypeScript type definitions for merge and alternate-merge Web Workers
- Implement custom rotation angle input with increment/decrement controls for rotate tool
- Extend delete-pages tool to render page thumbnails for better UX
- Hide number input spin buttons across all number inputs via CSS
- Refactor rotateAll function to accept angle parameter instead of direction multiplier
- Update fileHandler to support delete-pages tool thumbnail rendering
- Improve type safety in alternate-merge logic with proper interface definitions
- Enhance rotate tool UI with custom angle input field and adjustment buttons

src/js/handlers/fileHandler.ts

@@ -117,7 +117,7 @@ async function handleSinglePdfUpload(toolId, file) {
         .toString();
     }
 
-    if (toolId === 'organize' || toolId === 'rotate') {
+    if (toolId === 'organize' || toolId === 'rotate' || toolId === 'delete-pages') {
       await renderPageThumbnails(toolId, state.pdfDoc);
 
       if (toolId === 'rotate') {
@@ -134,14 +134,19 @@ async function handleSinglePdfUpload(toolId, file) {
         const rotateAllRightBtn = document.getElementById(
           'rotate-all-right-btn'
         );
+        const rotateAllCustomBtn = document.getElementById('rotate-all-custom-btn');
+        const rotateAllCustomInput = document.getElementById('custom-rotate-all-input') as HTMLInputElement;
+        const rotateAllDecrementBtn = document.getElementById('rotate-all-decrement-btn');
+        const rotateAllIncrementBtn = document.getElementById('rotate-all-increment-btn');
+
 
         rotateAllControls.classList.remove('hidden');
         createIcons({ icons });
 
-        const rotateAll = (direction) => {
+        const rotateAll = (angle: number) => {
           // Update rotation state for ALL pages (including unrendered ones)
           for (let i = 0; i < rotationState.length; i++) {
-            rotationState[i] = (rotationState[i] + direction * 90 + 360) % 360;
+            rotationState[i] = (rotationState[i] + angle);
           }
 
           // Update DOM for currently rendered pages
@@ -149,15 +154,44 @@ async function handleSinglePdfUpload(toolId, file) {
             const pageIndex = parseInt((item as HTMLElement).dataset.pageIndex || '0');
             const newRotation = rotationState[pageIndex];
             (item as HTMLElement).dataset.rotation = newRotation.toString();
+
             const thumbnail = item.querySelector('canvas, img');
             if (thumbnail) {
               (thumbnail as HTMLElement).style.transform =
                 `rotate(${newRotation}deg)`;
             }
+
+            const input = item.querySelector('input');
+            if (input) {
+              input.value = newRotation.toString();
+            }
           });
         };
-        rotateAllLeftBtn.onclick = () => rotateAll(-1);
-        rotateAllRightBtn.onclick = () => rotateAll(1);
+        rotateAllLeftBtn.onclick = () => rotateAll(-90);
+        rotateAllRightBtn.onclick = () => rotateAll(90);
+
+        if (rotateAllCustomBtn && rotateAllCustomInput) {
+          rotateAllCustomBtn.onclick = () => {
+            const angle = parseInt(rotateAllCustomInput.value);
+            if (!isNaN(angle) && angle !== 0) {
+              rotateAll(angle);
+            }
+          };
+
+          if (rotateAllDecrementBtn) {
+            rotateAllDecrementBtn.onclick = () => {
+              let current = parseInt(rotateAllCustomInput.value) || 0;
+              rotateAllCustomInput.value = (current - 1).toString();
+            };
+          }
+
+          if (rotateAllIncrementBtn) {
+            rotateAllIncrementBtn.onclick = () => {
+              let current = parseInt(rotateAllCustomInput.value) || 0;
+              rotateAllCustomInput.value = (current + 1).toString();
+            };
+          }
+        }
       }
     }