chore: update config files, icons and readme

- Update FUNDING.yml formatting
- Remove debug log in sanitize-pdf.ts
- Adjust test expectation for tool count
- Standardize dependabot.yml quotes
- Update tool icons in config
- Expand and reorganize README features list
- Fix markdown formatting in README

src/js/config/tools.ts

@@ -369,7 +369,7 @@ export const categories = [
       {
         id: 'posterize',
         name: 'Posterize PDF',
-        icon: 'layout-grid',
+        icon: 'notepad-text-dashed',
         subtitle: 'Split a large page into multiple smaller pages.',
       },
     ],
@@ -392,7 +392,7 @@ export const categories = [
       {
         id: 'linearize',
         name: 'Linearize PDF',
-        icon: 'zap',
+        icon: 'gauge',
         subtitle: 'Optimize PDF for fast web viewing.',
       },
       {
@@ -415,7 +415,7 @@ export const categories = [
       {
         id: 'sanitize-pdf',
         name: 'Sanitize PDF',
-        icon: 'shield-alert',
+        icon: 'brush-cleaning',
         subtitle: 'Remove metadata, annotations, scripts, and more.',
       },
       {