Posthog, scarf and url navigation overhaul (#4318)

Added post hog project - always enabled
Added scarf pixel - Always enabled 
Reworked Url navigation 
Forward and back now works without reloading page

---------

Co-authored-by: Connor Yoh <[email protected]>

frontend/src/utils/urlMapping.ts

@@ -0,0 +1,33 @@
+import { ToolId } from '../types/toolId';
+
+// Map URL paths to tool keys (multiple URLs can map to same tool)
+export const URL_TO_TOOL_MAP: Record<string, ToolId> = {
+  '/split-pdfs': 'split',
+  '/split': 'split',
+  '/merge-pdfs': 'mergePdfs',
+  '/compress-pdf': 'compress',
+  '/convert': 'convert',
+  '/convert-pdf': 'convert',
+  '/file-to-pdf': 'convert',
+  '/eml-to-pdf': 'convert',
+  '/html-to-pdf': 'convert',
+  '/markdown-to-pdf': 'convert',
+  '/pdf-to-csv': 'convert',
+  '/pdf-to-img': 'convert',
+  '/pdf-to-markdown': 'convert',
+  '/pdf-to-pdfa': 'convert',
+  '/pdf-to-word': 'convert',
+  '/pdf-to-xml': 'convert',
+  '/add-password': 'addPassword',
+  '/change-permissions': 'change-permissions',
+  '/sanitize-pdf': 'sanitize',
+  '/ocr': 'ocr',
+  '/ocr-pdf': 'ocr',
+  '/add-watermark': 'addWatermark',
+  '/remove-password': 'remove-password',
+  '/single-large-page': 'single-large-page',
+  '/repair': 'repair',
+  '/unlock-pdf-forms': 'unlock-pdf-forms',
+  '/remove-certificate-sign': 'remove-certificate-sign',
+  '/remove-cert-sign': 'remove-certificate-sign'
+};