feat(web): add customer portal with 7 sections and staff impersonation

Implements the customer-facing portal for pet parents with:
- Dashboard showing upcoming appointments, pet cards, loyalty rewards
- Multi-step appointment booking flow with recurring scheduling
- Pet profiles with medical/behavioral notes and vaccination tracking
- Grooming report cards with before/after, behavior assessment, sharing
- Billing & payments with invoices, saved methods, autopay, tips, packages
- Communication with chat-style messaging and notification preferences
- Account settings with personal info, password, pet management, agreements
- Staff impersonation mode with required reason, 30-min session timer,
  non-dismissable banner, viewport border, watermark, read-only enforcement,
  and full audit trail viewer

Also adds Tailwind CSS, lucide-react, and recharts as dependencies.

Closes #53

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

apps/web/vite.config.ts

@@ -1,10 +1,12 @@
 import { defineConfig } from "vite";
 import react from "@vitejs/plugin-react";
+import tailwindcss from "@tailwindcss/vite";
 import { VitePWA } from "vite-plugin-pwa";
 
 export default defineConfig({
   plugins: [
     react(),
+    tailwindcss(),
     VitePWA({
       registerType: "autoUpdate",
       includeAssets: ["favicon.svg", "apple-touch-icon.png"],