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/router.py

@@ -0,0 +1,76 @@
+import asyncio
+
+from fastapi import APIRouter, BackgroundTasks, Depends, Header, Query, Request, Response
+from sqlalchemy.ext.asyncio import AsyncSession
+
+from app.core.config import settings
+from app.core.database import get_db
+from app.core.dependencies import get_current_business
+from app.modules.whatsapp import schemas, service
+
+router = APIRouter()
+
+
+@router.post("/connect", response_model=dict)
+async def connect(
+    body: schemas.ConnectRequest,
+    business_id: int = Depends(get_current_business),
+    db: AsyncSession = Depends(get_db),
+):
+    await service.connect_whatsapp(db, business_id, body)
+    return {"detail": "WhatsApp conectado correctamente"}
+
+
+@router.get("/status", response_model=schemas.WhatsAppStatusRead)
+async def get_status(
+    business_id: int = Depends(get_current_business),
+    db: AsyncSession = Depends(get_db),
+):
+    from sqlalchemy import select
+    from app.modules.business.models import Business
+
+    result = await db.execute(select(Business).where(Business.id == business_id))
+    business = result.scalar_one_or_none()
+    return schemas.WhatsAppStatusRead(
+        connected=bool(business and business.whatsapp_phone_number_id),
+        phone_number_id=business.whatsapp_phone_number_id if business else None,
+        meta_business_id=business.meta_business_id if business else None,
+    )
+
+
+@router.post("/disconnect", status_code=204)
+async def disconnect(
+    business_id: int = Depends(get_current_business),
+    db: AsyncSession = Depends(get_db),
+):
+    await service.disconnect_whatsapp(db, business_id)
+    return Response(status_code=204)
+
+
+@router.get("/webhook")
+async def verify_webhook(
+    hub_mode: str | None = Query(default=None, alias="hub.mode"),
+    hub_verify_token: str | None = Query(default=None, alias="hub.verify_token"),
+    hub_challenge: str | None = Query(default=None, alias="hub.challenge"),
+):
+    """Verificación inicial del webhook por parte de Meta."""
+    if hub_mode == "subscribe" and hub_verify_token == settings.META_WEBHOOK_VERIFY_TOKEN:
+        return Response(content=hub_challenge, media_type="text/plain")
+    return Response(status_code=403)
+
+
+@router.post("/webhook", status_code=200)
+async def receive_webhook(
+    request: Request,
+    background_tasks: BackgroundTasks,
+    x_hub_signature_256: str | None = Header(default=None),
+    db: AsyncSession = Depends(get_db),
+):
+    """Recibe mensajes de Meta, valida firma y despacha al bot de forma asíncrona."""
+    body_bytes = await request.body()
+    service.verify_signature(body_bytes, x_hub_signature_256 or "")
+
+    payload = schemas.WebhookPayload.model_validate_json(body_bytes)
+    background_tasks.add_task(service.dispatch_webhook, db, payload)
+
+    return {"status": "ok"}