Feature/v2/add text (#4951)

Refactor sign to separate out add text and add image functions. 
Implement add text as standalone tool

frontend/src/core/utils/urlMapping.ts

@@ -96,6 +96,7 @@ export const URL_TO_TOOL_MAP: Record<string, ToolId> = {
   '/read': 'read',
   '/automate': 'automate',
   '/sign': 'sign',
+  '/add-text': 'addText',
 
   // Developer tools
   '/dev-api': 'devApi',