Configure ESLint with Prettier and TypeScript support.

- Baseline existing errors to warnings.
- Fix Image to PDF tool for HEIC and WebP inputs.
- Apply linting auto-fixes.

src/js/logic/bookmark-pdf.ts

@@ -771,8 +771,8 @@ let searchQuery = '';
 let csvBookmarks = null;
 let jsonBookmarks = null;
 let batchMode = false;
-let selectedBookmarks = new Set();
-let collapsedNodes = new Set();
+const selectedBookmarks = new Set();
+const collapsedNodes = new Set();
 
 const colorClasses = {
   red: 'bg-red-100 border-red-300',
@@ -1126,7 +1126,7 @@ async function renderPage(num, zoom = null, destX = null, destY = null) {
 
   const dpr = window.devicePixelRatio || 1;
 
-  let viewport = page.getViewport({ scale: zoomScale });
+  const viewport = page.getViewport({ scale: zoomScale });
   currentViewport = viewport;
 
   canvas.height = viewport.height * dpr;

src/js/logic/form-creator.ts

@@ -14,8 +14,8 @@ import { FormField, PageData } from '../types/index.js'
 let fields: FormField[] = []
 let selectedField: FormField | null = null
 let fieldCounter = 0
-let existingFieldNames: Set<string> = new Set()
-let existingRadioGroups: Set<string> = new Set()
+const existingFieldNames: Set<string> = new Set()
+const existingRadioGroups: Set<string> = new Set()
 let draggedElement: HTMLElement | null = null
 let offsetX = 0
 let offsetY = 0
@@ -2045,7 +2045,7 @@ async function renderCanvas(): Promise<void> {
     if (!currentPage) return
 
     // Fixed scale for better visibility
-    let scale = 1.333
+    const scale = 1.333
 
     currentScale = scale
 

src/js/logic/page-numbers-page.ts

@@ -162,7 +162,7 @@ async function addPageNumbers() {
             const xOffset = bounds.x || 0;
             const yOffset = bounds.y || 0;
 
-            let pageNumText = format === 'page_x_of_y' ? `${i + 1} / ${totalPages}` : `${i + 1}`;
+            const pageNumText = format === 'page_x_of_y' ? `${i + 1} / ${totalPages}` : `${i + 1}`;
 
             const textWidth = helveticaFont.widthOfTextAtSize(pageNumText, fontSize);
             const textHeight = fontSize;

src/js/logic/pdf-layers-page.ts

@@ -19,7 +19,7 @@ interface LayerData {
 
 let currentFile: File | null = null;
 let currentDoc: any = null;
-let layersMap = new Map<number, LayerData>();
+const layersMap = new Map<number, LayerData>();
 let nextDisplayOrder = 0;
 
 document.addEventListener('DOMContentLoaded', () => {

src/js/logic/posterize-page.ts

@@ -136,7 +136,7 @@ async function posterize() {
         const rows = parseInt((document.getElementById('posterize-rows') as HTMLInputElement).value) || 1;
         const cols = parseInt((document.getElementById('posterize-cols') as HTMLInputElement).value) || 1;
         const pageSizeKey = (document.getElementById('output-page-size') as HTMLSelectElement).value as keyof typeof PageSizes;
-        let orientation = (document.getElementById('output-orientation') as HTMLSelectElement).value;
+        const orientation = (document.getElementById('output-orientation') as HTMLSelectElement).value;
         const scalingMode = (document.querySelector('input[name="scaling-mode"]:checked') as HTMLInputElement).value;
         const overlap = parseFloat((document.getElementById('overlap') as HTMLInputElement).value) || 0;
         const overlapUnits = (document.getElementById('overlap-units') as HTMLSelectElement).value;