feat(api): add stats chart endpoint for admin access with time series data

feat(dayjs): integrate dayjs for date handling and formatting across the application
refactor(routes): update date handling in id-tags, transactions, users, and dashboard routes to use dayjs
style(globals): improve CSS variable definitions for better readability and consistency
deps: add dayjs as a dependency for date manipulation

pnpm-workspace.yaml

@@ -6,6 +6,7 @@ catalog:
   "@tanstack/react-query": ^5.90.21
   "@better-auth/passkey": "^1.5.4"
   "better-auth": "^1.5.4"
+  "dayjs": "^1.11.19"
 
 onlyBuiltDependencies:
   - sharp