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/core/security.py

@@ -0,0 +1,27 @@
+from datetime import datetime, timedelta, timezone
+
+import bcrypt
+from jose import jwt
+
+from app.core.config import settings
+
+
+def hash_password(password: str) -> str:
+    return bcrypt.hashpw(password.encode(), bcrypt.gensalt()).decode()
+
+
+def verify_password(plain: str, hashed: str) -> bool:
+    return bcrypt.checkpw(plain.encode(), hashed.encode())
+
+
+def create_access_token(data: dict, expires_delta: timedelta | None = None) -> str:
+    to_encode = data.copy()
+    expire = datetime.now(timezone.utc) + (
+        expires_delta or timedelta(minutes=settings.ACCESS_TOKEN_EXPIRE_MINUTES)
+    )
+    to_encode["exp"] = expire
+    return jwt.encode(to_encode, settings.SECRET_KEY, algorithm=settings.ALGORITHM)
+
+
+def decode_token(token: str) -> dict:
+    return jwt.decode(token, settings.SECRET_KEY, algorithms=[settings.ALGORITHM])