fix mixed content errors when wrapping urls with URL constructor

frontend-v2/server/routes.ts

···
     console.error("OAuth authorize error:", error);
 
     return Response.redirect(
-      new URL(
-        "/login?error=" +
-          encodeURIComponent("Please check your handle and try again."),
-        req.url,
-      ),
+      "/login?error=" +
+        encodeURIComponent("Please check your handle and try again."),
       302,
     );
   }
···
 
     if (!code || !state) {
       return Response.redirect(
-        new URL(
-          "/login?error=" + encodeURIComponent("Invalid OAuth callback"),
-          req.url,
-        ),
+        "/login?error=" + encodeURIComponent("Invalid OAuth callback"),
         302,
       );
     }
···
 
     if (!sessionId) {
       return Response.redirect(
-        new URL(
-          "/login?error=" + encodeURIComponent("Failed to create session"),
-          req.url,
-        ),
+        "/login?error=" + encodeURIComponent("Failed to create session"),
         302,
       );
     }
···
             ? "already_on_waitlist"
             : "invite_required";
           return Response.redirect(
-            new URL(`/waitlist?error=${errorCode}`, req.url),
+            `/waitlist?error=${errorCode}`,
             302,
           );
         }
···
     return new Response(null, {
       status: 302,
       headers: {
-        Location: new URL("/", req.url).toString(),
+        Location: "/",
         "Set-Cookie": sessionCookie,
       },
     });
   } catch (error) {
     console.error("OAuth callback error:", error);
     return Response.redirect(
-      new URL(
-        "/login?error=" + encodeURIComponent("Authentication failed"),
-        req.url,
-      ),
+      "/login?error=" + encodeURIComponent("Authentication failed"),
       302,
     );
   }
···
   return new Response(null, {
     status: 302,
     headers: {
-      Location: new URL("/login", req.url).toString(),
+      Location: "/login",
       "Set-Cookie": clearCookie,
     },
   });
···
   } catch (error) {
     console.error("Waitlist initiate error:", error);
     return Response.redirect(
-      new URL("/waitlist?error=authorization_failed", req.url),
+      "/waitlist?error=authorization_failed",
       302,
     );
   }
···
 
     if (!code || !state) {
       return Response.redirect(
-        new URL("/waitlist?error=invalid_callback", req.url),
+        "/waitlist?error=invalid_callback",
         302,
       );
     }
···
 
     if (!userInfo) {
       return Response.redirect(
-        new URL("/waitlist?error=no_user_info", req.url),
+        "/waitlist?error=no_user_info",
         302,
       );
     }
···
     if (!sliceUri) {
       console.error("Missing VITE_SLICE_URI environment variable");
       return Response.redirect(
-        new URL("/waitlist?error=waitlist_failed", req.url),
+        "/waitlist?error=waitlist_failed",
         302,
       );
     }
···
 
     // Redirect back to waitlist page with success parameter
     const handle = userInfo.name || waitlistData.handle || "user";
-    const redirectUrl = new URL("/waitlist", req.url);
-    redirectUrl.searchParams.set("waitlist", "success");
-    redirectUrl.searchParams.set("handle", handle);
-    return Response.redirect(redirectUrl.toString(), 302);
+    const params = new URLSearchParams({
+      waitlist: "success",
+      handle,
+    });
+    return Response.redirect(`/waitlist?${params.toString()}`, 302);
   } catch (error) {
     console.error("Waitlist callback error:", error);
     return Response.redirect(
-      new URL("/waitlist?error=waitlist_failed", req.url),
+      "/waitlist?error=waitlist_failed",
       302,
     );
   }