feat: initial commit — HermesMessages SaaS platform

Backend (FastAPI + Python 3.12):
- Multi-tenant auth with JWT: login, register, refresh, Meta OAuth
- Business & BusinessConfig management
- WhatsApp webhook with HMAC signature verification
- Bot engine powered by Claude AI
- Calendar availability with Redis caching
- Reservations CRUD with status management
- Dashboard analytics (stats, agenda, peak hours)
- Billing & plan management
- Admin panel with platform-wide stats
- Async bcrypt via asyncio.to_thread
- IntegrityError handling for concurrent registration race conditions

Frontend (React 18 + Vite + Tailwind CSS):
- Multi-step guided registration form with helper text on every field
- Login page with show/hide password toggle
- Protected routes with AuthContext
- Dashboard with stats cards, bar chart, and daily agenda
- Reservations list with search, filters, and inline status actions
- Calendar with weekly view, slot availability, and date blocking
- Config page: business info, schedules, bot personality
- Billing page with plan comparison and usage bar

Design system:
- Bricolage Grotesque + DM Sans typography
- Emerald primary palette with semantic color tokens
- scale(0.97) button press feedback, ease-out animations
- Skeleton loaders, stagger animations, prefers-reduced-motion support
- Accessible: aria-labels, visible focus rings, 4.5:1 contrast

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

frontend/src/lib/utils.js

@@ -0,0 +1,65 @@
+import { clsx } from 'clsx'
+import { twMerge } from 'tailwind-merge'
+
+export function cn(...inputs) {
+  return twMerge(clsx(inputs))
+}
+
+export function formatDate(dateStr, opts = {}) {
+  if (!dateStr) return '—'
+  const d = new Date(dateStr)
+  return d.toLocaleDateString('es-ES', {
+    day: '2-digit', month: 'short', year: 'numeric', ...opts,
+  })
+}
+
+export function formatTime(timeStr) {
+  if (!timeStr) return '—'
+  return timeStr.slice(0, 5)
+}
+
+export function formatDateTime(dateStr) {
+  if (!dateStr) return '—'
+  const d = new Date(dateStr)
+  return d.toLocaleString('es-ES', {
+    day: '2-digit', month: 'short', hour: '2-digit', minute: '2-digit',
+  })
+}
+
+export const STATUS_LABELS = {
+  pending: 'Pendiente',
+  confirmed: 'Confirmada',
+  cancelled: 'Cancelada',
+  no_show: 'No asistió',
+}
+
+export const STATUS_BADGE = {
+  pending: 'badge-yellow',
+  confirmed: 'badge-green',
+  cancelled: 'badge-red',
+  no_show: 'badge-gray',
+}
+
+export const BUSINESS_TYPES = [
+  { value: 'restaurant', label: 'Restaurante' },
+  { value: 'clinic', label: 'Clínica / Consultorio' },
+  { value: 'salon', label: 'Salón de belleza' },
+  { value: 'spa', label: 'Spa / Bienestar' },
+  { value: 'barbershop', label: 'Barbería' },
+  { value: 'gym', label: 'Gimnasio / Entrenador' },
+  { value: 'other', label: 'Otro' },
+]
+
+export const TIMEZONES = [
+  { value: 'America/Bogota', label: 'Bogotá (UTC-5)' },
+  { value: 'America/Mexico_City', label: 'Ciudad de México (UTC-6)' },
+  { value: 'America/Lima', label: 'Lima (UTC-5)' },
+  { value: 'America/Santiago', label: 'Santiago (UTC-4)' },
+  { value: 'America/Buenos_Aires', label: 'Buenos Aires (UTC-3)' },
+  { value: 'America/Caracas', label: 'Caracas (UTC-4)' },
+  { value: 'Europe/Madrid', label: 'Madrid (UTC+1/+2)' },
+  { value: 'UTC', label: 'UTC' },
+]
+
+export const DAYS_ES = ['Lun', 'Mar', 'Mié', 'Jue', 'Vie', 'Sáb', 'Dom']
+export const DAYS_FULL = ['Lunes', 'Martes', 'Miércoles', 'Jueves', 'Viernes', 'Sábado', 'Domingo']