Add Token model and update endpoints to use it

Refactor token validation and saving endpoints to accept a Token model
instead of a raw string. Set default values for token generation request
fields. Update TokenService cleanup to use datetime.now().

microservices/token-service/models.py

@@ -6,6 +6,9 @@ from pydantic import BaseModel, Field
 from typing import List, Optional, Dict, Any
 from datetime import datetime
 
+class Token(BaseModel):
+    token: str = Field(..., description="JWT token")
+
 class TokenGenerateRequest(BaseModel):
     """Request model for token generation"""
     name: str = Field(..., description="Token owner name")
@@ -48,8 +51,8 @@ class HealthResponse(BaseModel):
     status: str
     timestamp: datetime
     version: str
-    
+
     class Config:
         json_encoders = {
             datetime: lambda v: v.isoformat()
-        }
+        }