fix: currency converter and auth apis

app/api/currency/route.ts

@@ -1,6 +1,6 @@
 import { getSession } from "@/lib/auth"
 import { PoorManCache } from "@/lib/cache"
-import { format } from "date-fns"
+import { format, isSameDay, subDays } from "date-fns"
 import { NextRequest, NextResponse } from "next/server"
 
 type HistoricRate = {
@@ -36,11 +36,17 @@ export async function GET(request: NextRequest) {
       return NextResponse.json({ error: "Missing required parameters: from, to, date" }, { status: 400 })
     }
 
-    const date = new Date(dateParam)
+    let date = new Date(dateParam)
+
     if (isNaN(date.getTime())) {
       return NextResponse.json({ error: "Invalid date format" }, { status: 400 })
     }
 
+    // hack to get yesterday's rate if it's today
+    if (isSameDay(date, new Date())) {
+      date = subDays(date, 1)
+    }
+
     const formattedDate = format(date, "yyyy-MM-dd")
 
     // Check cache first