feat: module toggles in POS config and Instance Manager

- Add GET/PUT /pos/api/config/modules endpoints in POS config_bp.py
- Update sidebar.js to filter nav items based on enabled modules
- Add Modules section to POS config.html with toggles for WhatsApp, Marketplace, MercadoLibre
- Add module load/save logic to POS config.js
- Preload modules in app-init.js for sidebar caching

- Add tenant module management to Instance Manager
  - get_tenant_modules / update_tenant_modules in tenant_service.py
  - GET/PUT /api/tenants/<id>/modules endpoints in tenants_bp.py
  - Add modules modal to manager index.html
  - Add module editing UI and logic to manager.js
  - Add toggle-switch CSS to manager.css

pos/migrations/v3.5_whatsapp_state_machine.sql

@@ -0,0 +1,100 @@
+-- ============================================================
+-- v3.5 WhatsApp State Machine
+-- Reorganización del chatbot de AI libre a flujo estructurado
+-- ============================================================
+
+-- 1. Extender whatsapp_sessions con estado y contexto
+-- ---------------------------------------------------
+ALTER TABLE whatsapp_sessions
+ADD COLUMN IF NOT EXISTS state VARCHAR(50) DEFAULT 'idle',
+ADD COLUMN IF NOT EXISTS state_data JSONB DEFAULT '{}',
+ADD COLUMN IF NOT EXISTS customer_id INTEGER REFERENCES customers(id),
+ADD COLUMN IF NOT EXISTS branch_id INTEGER REFERENCES branches(id),
+ADD COLUMN IF NOT EXISTS learning_cycle INTEGER DEFAULT 0,
+ADD COLUMN IF NOT EXISTS created_at TIMESTAMPTZ DEFAULT NOW();
+
+-- Índices para lookups rápidos de sesión
+CREATE INDEX IF NOT EXISTS idx_wa_sessions_state ON whatsapp_sessions(state);
+CREATE INDEX IF NOT EXISTS idx_wa_sessions_customer ON whatsapp_sessions(customer_id);
+CREATE INDEX IF NOT EXISTS idx_wa_sessions_updated ON whatsapp_sessions(updated_at);
+
+-- 2. Tabla de vínculo persistente WA ID ↔ Cliente
+-- ------------------------------------------------
+CREATE TABLE IF NOT EXISTS wa_customer_links (
+    phone VARCHAR(50) PRIMARY KEY,
+    customer_id INTEGER NOT NULL REFERENCES customers(id),
+    created_at TIMESTAMPTZ DEFAULT NOW(),
+    updated_at TIMESTAMPTZ DEFAULT NOW()
+);
+
+CREATE INDEX IF NOT EXISTS idx_wa_cust_link_customer ON wa_customer_links(customer_id);
+
+-- Trigger para updated_at
+CREATE OR REPLACE FUNCTION update_wa_link_timestamp()
+RETURNS TRIGGER AS $$
+BEGIN
+    NEW.updated_at = NOW();
+    RETURN NEW;
+END;
+$$ LANGUAGE plpgsql;
+
+DROP TRIGGER IF EXISTS trg_wa_link_updated ON wa_customer_links;
+CREATE TRIGGER trg_wa_link_updated
+    BEFORE UPDATE ON wa_customer_links
+    FOR EACH ROW EXECUTE FUNCTION update_wa_link_timestamp();
+
+-- 3. Tabla de sesiones de aprendizaje (piezas no resueltas)
+-- ---------------------------------------------------------
+CREATE TABLE IF NOT EXISTS wa_learning_sessions (
+    id SERIAL PRIMARY KEY,
+    phone VARCHAR(50) NOT NULL,
+    customer_id INTEGER REFERENCES customers(id),
+    description TEXT NOT NULL,
+    offered_parts JSONB DEFAULT '[]',
+    status VARCHAR(20) DEFAULT 'pending',
+    resolved_part_id INTEGER REFERENCES inventory(id),
+    resolution_sale_id INTEGER REFERENCES sales(id),
+    created_at TIMESTAMPTZ DEFAULT NOW(),
+    resolved_at TIMESTAMPTZ
+);
+
+CREATE INDEX IF NOT EXISTS idx_wa_learn_phone ON wa_learning_sessions(phone);
+CREATE INDEX IF NOT EXISTS idx_wa_learn_status ON wa_learning_sessions(status);
+CREATE INDEX IF NOT EXISTS idx_wa_learn_customer ON wa_learning_sessions(customer_id);
+CREATE INDEX IF NOT EXISTS idx_wa_learn_created ON wa_learning_sessions(created_at);
+
+-- 4. Tabla de configuración de envío por sucursal
+-- ------------------------------------------------
+CREATE TABLE IF NOT EXISTS branch_delivery_config (
+    id SERIAL PRIMARY KEY,
+    branch_id INTEGER NOT NULL UNIQUE REFERENCES branches(id),
+    is_enabled BOOLEAN DEFAULT FALSE,
+    delivery_fee NUMERIC(12,2) DEFAULT 0,
+    free_delivery_threshold NUMERIC(12,2) DEFAULT NULL,
+    coverage_radius_km INTEGER DEFAULT NULL,
+    delivery_hours VARCHAR(100) DEFAULT 'Lun-Vie 9:00-18:00',
+    notes TEXT,
+    created_at TIMESTAMPTZ DEFAULT NOW(),
+    updated_at TIMESTAMPTZ DEFAULT NOW()
+);
+
+-- 5. Agregar push_name a whatsapp_messages (schema drift existente)
+-- ------------------------------------------------------------------
+ALTER TABLE whatsapp_messages
+ADD COLUMN IF NOT EXISTS push_name VARCHAR(200);
+
+-- 6. Migrar datos existentes: vincular por teléfono
+-- --------------------------------------------------
+-- Intentar vincular sesiones WA existentes con customers por teléfono
+INSERT INTO wa_customer_links (phone, customer_id)
+SELECT ws.phone, c.id
+FROM whatsapp_sessions ws
+JOIN customers c ON c.phone = ws.phone
+WHERE ws.phone IS NOT NULL AND c.phone IS NOT NULL
+ON CONFLICT (phone) DO NOTHING;
+
+-- Actualizar customer_id en whatsapp_sessions desde el vínculo
+UPDATE whatsapp_sessions ws
+SET customer_id = wcl.customer_id
+FROM wa_customer_links wcl
+WHERE ws.phone = wcl.phone AND ws.customer_id IS NULL;