feat(backend): update consistent Pydantic v2 use everywhere

7project/backend/app/schemas/category.py

@@ -1,23 +1,16 @@
 from typing import Optional
-from pydantic import BaseModel
-try:
-    # Pydantic v2
-    from pydantic import ConfigDict  # type: ignore
-    _HAS_V2 = True
-except Exception:  # pragma: no cover
-    _HAS_V2 = False
+from pydantic import BaseModel, ConfigDict
+
 
 class CategoryBase(BaseModel):
     name: str
     description: Optional[str] = None
 
+
 class CategoryCreate(CategoryBase):
     pass
 
+
 class CategoryRead(CategoryBase):
     id: int
-    if _HAS_V2:
-        model_config = ConfigDict(from_attributes=True)  # type: ignore
-    else:  # Pydantic v1 fallback
-        class Config:  # type: ignore
-            orm_mode = True
+    model_config = ConfigDict(from_attributes=True)

7project/backend/app/schemas/transaction.py

@@ -1,5 +1,6 @@
 from typing import List, Optional
-from pydantic import BaseModel, Field
+from pydantic import BaseModel, Field, ConfigDict
+
 
 class TransactionBase(BaseModel):
     amount: float = Field(..., gt=-1e18, lt=1e18)
@@ -17,5 +18,4 @@ class TransactionRead(TransactionBase):
     id: int
     category_ids: List[int] = []
 
-    class Config:
-        from_attributes = True
+    model_config = ConfigDict(from_attributes=True)