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/modules/whatsapp/schemas.py

@@ -0,0 +1,49 @@
+from pydantic import BaseModel
+
+
+class ConnectRequest(BaseModel):
+    access_token: str
+    phone_number_id: str
+    meta_business_id: str
+
+
+class WhatsAppStatusRead(BaseModel):
+    connected: bool
+    phone_number_id: str | None
+    meta_business_id: str | None
+
+
+# --- Estructuras del payload de Meta ---
+
+class WhatsAppTextMessage(BaseModel):
+    body: str
+
+
+class WhatsAppMessage(BaseModel):
+    from_: str
+    id: str
+    type: str
+    text: WhatsAppTextMessage | None = None
+
+    model_config = {"populate_by_name": True}
+
+
+class WhatsAppValue(BaseModel):
+    messaging_product: str
+    metadata: dict
+    messages: list[WhatsAppMessage] | None = None
+
+
+class WhatsAppChange(BaseModel):
+    value: WhatsAppValue
+    field: str
+
+
+class WhatsAppEntry(BaseModel):
+    id: str
+    changes: list[WhatsAppChange]
+
+
+class WebhookPayload(BaseModel):
+    object: str
+    entry: list[WhatsAppEntry]