fix(web): use relative URL for Better-Auth client, fix lint errors

- auth-client.ts: default baseURL to empty string (relative URL via nginx
  proxy) instead of http://localhost:3000 which breaks deployed environments
- Dashboard.tsx: remove unused Appointment type import (lint error)

Co-Authored-By: Paperclip <noreply@paperclip.ing>

apps/web/src/lib/auth-client.ts

@@ -1,7 +1,7 @@
 import { createAuthClient } from "better-auth/react";
 
 export const authClient = createAuthClient({
-  baseURL: import.meta.env.VITE_API_URL ?? "http://localhost:3000",
+  baseURL: import.meta.env.VITE_API_URL ?? "",
 });
 
 export const { signIn, signOut, useSession } = authClient;

apps/web/src/portal/sections/Dashboard.tsx

@@ -1,6 +1,5 @@
 import { Calendar, Clock, PawPrint, CreditCard, Star, ChevronRight, AlertTriangle } from "lucide-react";
 import { PETS, UPCOMING_APPOINTMENTS, PAST_APPOINTMENTS, INVOICES, LOYALTY, BUSINESS_NAME } from "../mockData.js";
-import type { Appointment } from "../mockData.js";
 
 interface Props {
   onNavigate: (section: "appointments" | "pets" | "billing" | "reports") => void;