Fix backend deprecation warnings and duplicate index

- Remove duplicate index definition in Task model
- Update Query regex to pattern parameter
- Use ConfigDict instead of class Config in Pydantic

backend/app/models.py

@@ -17,7 +17,3 @@ class Task(Base):
     is_done = Column(Boolean, default=False)
     created_at = Column(DateTime, default=datetime.utcnow)
     updated_at = Column(DateTime, default=datetime.utcnow, onupdate=datetime.utcnow)
-
-    __table_args__ = (
-        Index("ix_tasks_date", "date"),
-    )

backend/app/routes.py

@@ -27,7 +27,7 @@ def health_check():
 @router.get("/tasks", response_model=list[TaskResponse])
 def get_tasks(
     date: str = Query(..., pattern=r"^\d{4}-\d{2}-\d{2}$"),
-    status: Optional[str] = Query(None, regex="^(all|active|done)$"),
+    status: Optional[str] = Query(None, pattern="^(all|active|done)$"),
     service: TaskService = Depends(get_task_service),
 ):
     tasks = service.get_tasks_by_date(date, status)

backend/app/schemas.py

@@ -1,7 +1,7 @@
 from datetime import datetime
 from enum import Enum
 from typing import Optional
-from pydantic import BaseModel, Field
+from pydantic import BaseModel, ConfigDict, Field
 
 
 class Priority(str, Enum):
@@ -32,14 +32,13 @@ class TaskUpdate(BaseModel):
 
 
 class TaskResponse(TaskBase):
+    model_config = ConfigDict(from_attributes=True)
+
     id: str
     is_done: bool
     created_at: Optional[datetime]
     updated_at: Optional[datetime]
 
-    class Config:
-        from_attributes = True
-
 
 class RescheduleRequest(BaseModel):
     target_date: str = Field(..., pattern=r"^\d{4}-\d{2}-\d{2}$")