feat(avatar): add user token accounting

digital-avatar-app/backend/models.py

@@ -1,6 +1,7 @@
 import uuid
 
 from sqlalchemy import (
+    BigInteger,
     Boolean,
     Column,
     DateTime,
@@ -259,14 +260,42 @@ class KnowledgeChunk(Base):
 class TokenAccount(Base):
     __tablename__ = "token_account"
     id = Column(Integer, primary_key=True)
-    balance = Column(Integer, default=1250)
+    user_id = Column(String, nullable=False, default="", index=True)
+    balance = Column(BigInteger, default=1_000_000)
+    total_granted = Column(BigInteger, default=1_000_000)
+    total_consumed = Column(BigInteger, default=0)
+    created_at = Column(DateTime, server_default=func.now())
+    updated_at = Column(DateTime, server_default=func.now(), onupdate=func.now())
+
+
+class TokenUsage(Base):
+    __tablename__ = "token_usage"
+    __table_args__ = (
+        Index("ix_token_usage_user_created", "user_id", "created_at"),
+        Index("ix_token_usage_avatar_created", "avatar_id", "created_at"),
+    )
+
+    id = Column(String, primary_key=True, default=lambda: uuid.uuid4().hex)
+    user_id = Column(String, nullable=False, index=True)
+    avatar_id = Column(String, nullable=False, default="", index=True)
+    source = Column(String, nullable=False, default="chat")
+    model = Column(String, default="")
+    status = Column(String, nullable=False, default="reserved")
+    reserved_tokens = Column(BigInteger, default=0)
+    prompt_tokens = Column(BigInteger, default=0)
+    completion_tokens = Column(BigInteger, default=0)
+    total_tokens = Column(BigInteger, default=0)
+    balance_after = Column(BigInteger, default=0)
+    failure_reason = Column(String, default="")
+    created_at = Column(DateTime, server_default=func.now())
+    settled_at = Column(DateTime)
 
 
 class TokenPlan(Base):
     __tablename__ = "token_plans"
     id = Column(String, primary_key=True)
     name = Column(String, default="")
-    amount = Column(Integer, default=0)
+    amount = Column(BigInteger, default=0)
     price = Column(Float, default=0)
     badge = Column(String, default="")
     desc = Column(String, default="")