feat: add Layer 2 - WhatsApp Core logic, API Gateway models/auth, Frontend core

WhatsApp Core:
- SessionManager with Baileys integration for multi-account support
- Express server with REST API and Socket.IO for real-time events
- Session lifecycle management (create, disconnect, delete)
- Message sending with support for text, image, document, audio, video

API Gateway:
- Database models: User, WhatsAppAccount, Contact, Conversation, Message
- JWT authentication with access/refresh tokens
- Auth endpoints: login, refresh, register, me
- Pydantic schemas for request/response validation

Frontend:
- React 18 app structure with routing
- Zustand auth store with persistence
- API client with automatic token handling
- Base CSS and TypeScript declarations

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

services/api-gateway/app/models/__init__.py

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+from app.models.user import User
+from app.models.whatsapp import WhatsAppAccount, Contact, Conversation, Message
+
+__all__ = ["User", "WhatsAppAccount", "Contact", "Conversation", "Message"]

services/api-gateway/app/models/user.py

@@ -0,0 +1,33 @@
+import uuid
+from datetime import datetime
+from sqlalchemy import Column, String, Boolean, DateTime, Enum as SQLEnum
+from sqlalchemy.dialects.postgresql import UUID
+import enum
+from app.core.database import Base
+
+
+class UserRole(str, enum.Enum):
+    ADMIN = "admin"
+    SUPERVISOR = "supervisor"
+    AGENT = "agent"
+
+
+class UserStatus(str, enum.Enum):
+    ONLINE = "online"
+    OFFLINE = "offline"
+    AWAY = "away"
+    BUSY = "busy"
+
+
+class User(Base):
+    __tablename__ = "users"
+
+    id = Column(UUID(as_uuid=True), primary_key=True, default=uuid.uuid4)
+    email = Column(String(255), unique=True, nullable=False, index=True)
+    password_hash = Column(String(255), nullable=False)
+    name = Column(String(100), nullable=False)
+    role = Column(SQLEnum(UserRole), default=UserRole.AGENT, nullable=False)
+    status = Column(SQLEnum(UserStatus), default=UserStatus.OFFLINE, nullable=False)
+    is_active = Column(Boolean, default=True, nullable=False)
+    created_at = Column(DateTime, default=datetime.utcnow, nullable=False)
+    updated_at = Column(DateTime, default=datetime.utcnow, onupdate=datetime.utcnow, nullable=False)

services/api-gateway/app/models/whatsapp.py

@@ -0,0 +1,111 @@
+import uuid
+from datetime import datetime
+from sqlalchemy import Column, String, Boolean, DateTime, Text, Integer, ForeignKey, Enum as SQLEnum
+from sqlalchemy.dialects.postgresql import UUID, JSONB, ARRAY
+from sqlalchemy.orm import relationship
+import enum
+from app.core.database import Base
+
+
+class AccountStatus(str, enum.Enum):
+    CONNECTING = "connecting"
+    CONNECTED = "connected"
+    DISCONNECTED = "disconnected"
+
+
+class ConversationStatus(str, enum.Enum):
+    BOT = "bot"
+    WAITING = "waiting"
+    ACTIVE = "active"
+    RESOLVED = "resolved"
+
+
+class MessageDirection(str, enum.Enum):
+    INBOUND = "inbound"
+    OUTBOUND = "outbound"
+
+
+class MessageType(str, enum.Enum):
+    TEXT = "text"
+    IMAGE = "image"
+    AUDIO = "audio"
+    VIDEO = "video"
+    DOCUMENT = "document"
+    LOCATION = "location"
+    CONTACT = "contact"
+    STICKER = "sticker"
+    BUTTONS = "buttons"
+    LIST = "list"
+
+
+class MessageStatus(str, enum.Enum):
+    PENDING = "pending"
+    SENT = "sent"
+    DELIVERED = "delivered"
+    READ = "read"
+    FAILED = "failed"
+
+
+class WhatsAppAccount(Base):
+    __tablename__ = "whatsapp_accounts"
+
+    id = Column(UUID(as_uuid=True), primary_key=True, default=uuid.uuid4)
+    phone_number = Column(String(20), nullable=True)
+    name = Column(String(100), nullable=False)
+    status = Column(SQLEnum(AccountStatus), default=AccountStatus.DISCONNECTED, nullable=False)
+    session_data = Column(JSONB, nullable=True)
+    qr_code = Column(Text, nullable=True)
+    created_at = Column(DateTime, default=datetime.utcnow, nullable=False)
+
+    conversations = relationship("Conversation", back_populates="whatsapp_account")
+
+
+class Contact(Base):
+    __tablename__ = "contacts"
+
+    id = Column(UUID(as_uuid=True), primary_key=True, default=uuid.uuid4)
+    phone_number = Column(String(20), unique=True, nullable=False, index=True)
+    name = Column(String(100), nullable=True)
+    email = Column(String(255), nullable=True)
+    company = Column(String(100), nullable=True)
+    metadata = Column(JSONB, default=dict)
+    tags = Column(ARRAY(String), default=list)
+    odoo_partner_id = Column(Integer, nullable=True)
+    created_at = Column(DateTime, default=datetime.utcnow, nullable=False)
+
+    conversations = relationship("Conversation", back_populates="contact")
+
+
+class Conversation(Base):
+    __tablename__ = "conversations"
+
+    id = Column(UUID(as_uuid=True), primary_key=True, default=uuid.uuid4)
+    whatsapp_account_id = Column(UUID(as_uuid=True), ForeignKey("whatsapp_accounts.id"), nullable=False)
+    contact_id = Column(UUID(as_uuid=True), ForeignKey("contacts.id"), nullable=False)
+    assigned_to = Column(UUID(as_uuid=True), ForeignKey("users.id"), nullable=True)
+    status = Column(SQLEnum(ConversationStatus), default=ConversationStatus.BOT, nullable=False)
+    last_message_at = Column(DateTime, nullable=True)
+    created_at = Column(DateTime, default=datetime.utcnow, nullable=False)
+
+    whatsapp_account = relationship("WhatsAppAccount", back_populates="conversations")
+    contact = relationship("Contact", back_populates="conversations")
+    messages = relationship("Message", back_populates="conversation", order_by="Message.created_at")
+
+
+class Message(Base):
+    __tablename__ = "messages"
+
+    id = Column(UUID(as_uuid=True), primary_key=True, default=uuid.uuid4)
+    conversation_id = Column(UUID(as_uuid=True), ForeignKey("conversations.id"), nullable=False)
+    whatsapp_message_id = Column(String(100), nullable=True)
+    direction = Column(SQLEnum(MessageDirection), nullable=False)
+    type = Column(SQLEnum(MessageType), default=MessageType.TEXT, nullable=False)
+    content = Column(Text, nullable=True)
+    media_url = Column(String(500), nullable=True)
+    metadata = Column(JSONB, default=dict)
+    sent_by = Column(UUID(as_uuid=True), ForeignKey("users.id"), nullable=True)
+    is_internal_note = Column(Boolean, default=False, nullable=False)
+    status = Column(SQLEnum(MessageStatus), default=MessageStatus.PENDING, nullable=False)
+    created_at = Column(DateTime, default=datetime.utcnow, nullable=False)
+
+    conversation = relationship("Conversation", back_populates="messages")