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>

backend/app/main.py

@@ -0,0 +1,40 @@
+from fastapi import FastAPI
+from fastapi.middleware.cors import CORSMiddleware
+
+from app.core.config import settings
+from app.core.errors import global_exception_handler
+
+app = FastAPI(
+    title="HermesMessages API",
+    description="Plataforma SaaS de automatización de reservas via WhatsApp",
+    version="0.1.0",
+)
+
+app.add_middleware(
+    CORSMiddleware,
+    allow_origins=["*"] if settings.ENVIRONMENT == "development" else [],
+    allow_credentials=True,
+    allow_methods=["*"],
+    allow_headers=["*"],
+)
+
+app.add_exception_handler(Exception, global_exception_handler)
+
+# Routers — se van añadiendo por módulo
+from app.modules.auth.router import router as auth_router
+from app.modules.business.router import router as business_router
+from app.modules.whatsapp.router import router as whatsapp_router
+from app.modules.calendar.router import router as calendar_router
+from app.modules.reservations.router import router as reservations_router
+from app.modules.dashboard.router import router as dashboard_router
+from app.modules.billing.router import router as billing_router
+from app.modules.admin.router import router as admin_router
+
+app.include_router(auth_router, prefix="/auth", tags=["auth"])
+app.include_router(business_router, prefix="/business", tags=["business"])
+app.include_router(whatsapp_router, prefix="/whatsapp", tags=["whatsapp"])
+app.include_router(calendar_router, prefix="/calendar", tags=["calendar"])
+app.include_router(reservations_router, prefix="/reservations", tags=["reservations"])
+app.include_router(dashboard_router, prefix="/dashboard", tags=["dashboard"])
+app.include_router(billing_router, prefix="/billing", tags=["billing"])
+app.include_router(admin_router, prefix="/admin", tags=["admin"])