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/calendar/service.py

@@ -0,0 +1,135 @@
+import json
+from datetime import date, datetime, time, timedelta
+
+import redis.asyncio as aioredis
+from fastapi import HTTPException, status
+from sqlalchemy import and_, func, select
+from sqlalchemy.ext.asyncio import AsyncSession
+
+from app.modules.business.models import BusinessConfig
+from app.modules.business.service import get_business_config
+from app.modules.calendar.schemas import DayAvailability, SlotRead
+from app.modules.reservations.models import Reservation
+
+SLOTS_CACHE_TTL = 300  # 5 minutos
+
+
+def _cache_key(business_id: int, target_date: date) -> str:
+    return f"slots:{business_id}:{target_date.isoformat()}"
+
+
+def _generate_slots(open_time: time, close_time: time, slot_duration: int) -> list[tuple[time, time]]:
+    slots = []
+    base = date.today()
+    current = datetime.combine(base, open_time)
+    end = datetime.combine(base, close_time)
+    delta = timedelta(minutes=slot_duration)
+    while current + delta <= end:
+        slots.append((current.time(), (current + delta).time()))
+        current += delta
+    return slots
+
+
+async def _count_reservations_per_slot(
+    db: AsyncSession,
+    business_id: int,
+    target_date: date,
+    slots: list[tuple[time, time]],
+) -> dict[tuple[time, time], int]:
+    result = await db.execute(
+        select(Reservation.time_start, func.count(Reservation.id))
+        .where(
+            and_(
+                Reservation.business_id == business_id,
+                Reservation.date == target_date,
+                Reservation.status.in_(["pending", "confirmed"]),
+            )
+        )
+        .group_by(Reservation.time_start)
+    )
+    counts = {row[0]: row[1] for row in result.all()}
+    return {slot: counts.get(slot[0], 0) for slot in slots}
+
+
+async def get_available_slots(
+    db: AsyncSession,
+    redis: aioredis.Redis,
+    business_id: int,
+    target_date: date,
+) -> DayAvailability:
+    cache_key = _cache_key(business_id, target_date)
+    cached = await redis.get(cache_key)
+    if cached:
+        return DayAvailability.model_validate_json(cached)
+
+    config = await get_business_config(db, business_id)
+
+    is_open = (
+        target_date.weekday() in (config.open_days or [])
+        and target_date not in (config.blocked_dates or [])
+    )
+
+    if not is_open:
+        result = DayAvailability(date=target_date, is_open=False, slots=[])
+        await redis.setex(cache_key, SLOTS_CACHE_TTL, result.model_dump_json())
+        return result
+
+    raw_slots = _generate_slots(config.open_time, config.close_time, config.slot_duration)
+    counts = await _count_reservations_per_slot(db, business_id, target_date, raw_slots)
+
+    slots = [
+        SlotRead(
+            time_start=s[0],
+            time_end=s[1],
+            available=max(0, config.max_per_slot - counts[s]),
+            max_per_slot=config.max_per_slot,
+        )
+        for s in raw_slots
+    ]
+
+    result = DayAvailability(date=target_date, is_open=True, slots=slots)
+    await redis.setex(cache_key, SLOTS_CACHE_TTL, result.model_dump_json())
+    return result
+
+
+async def get_availability_range(
+    db: AsyncSession,
+    redis: aioredis.Redis,
+    business_id: int,
+    start: date,
+    end: date,
+) -> list[DayAvailability]:
+    if (end - start).days > 31:
+        raise HTTPException(
+            status_code=status.HTTP_400_BAD_REQUEST,
+            detail="El rango máximo es 31 días",
+        )
+    days = []
+    current = start
+    while current <= end:
+        days.append(await get_available_slots(db, redis, business_id, current))
+        current += timedelta(days=1)
+    return days
+
+
+async def invalidate_slots_cache(redis: aioredis.Redis, business_id: int, target_date: date) -> None:
+    await redis.delete(_cache_key(business_id, target_date))
+
+
+async def add_blocked_date(db: AsyncSession, business_id: int, target_date: date) -> None:
+    config = await get_business_config(db, business_id)
+    blocked = list(config.blocked_dates or [])
+    if target_date not in blocked:
+        blocked.append(target_date)
+        config.blocked_dates = blocked
+        await db.commit()
+
+
+async def remove_blocked_date(db: AsyncSession, business_id: int, target_date: date) -> None:
+    config = await get_business_config(db, business_id)
+    blocked = list(config.blocked_dates or [])
+    if target_date not in blocked:
+        raise HTTPException(status_code=status.HTTP_404_NOT_FOUND, detail="Fecha no bloqueada")
+    blocked.remove(target_date)
+    config.blocked_dates = blocked
+    await db.commit()