fix: use timezone=true on flow_version created_at field (#12180)

* use timezone=true on flow_version created_at field

* add refresh on creation of entry

src/backend/base/langflow/services/database/models/flow_version/crud.py

@@ -55,6 +55,7 @@ async def create_flow_version_entry(
             async with session.begin_nested():
                 session.add(entry)
                 await session.flush()
+                await session.refresh(entry)
             break
         except IntegrityError as exc:
             if "unique_flow_version_number" not in str(exc).lower():

src/backend/base/langflow/services/database/models/flow_version/model.py

@@ -5,7 +5,7 @@ from uuid import UUID, uuid4
 
 from pydantic import BaseModel, computed_field, field_serializer
 from pydantic import Field as PydanticField
-from sqlalchemy import CheckConstraint, Column, ForeignKey, UniqueConstraint
+from sqlalchemy import CheckConstraint, Column, DateTime, ForeignKey, UniqueConstraint, func
 from sqlmodel import JSON, Field, SQLModel
 
 
@@ -23,7 +23,9 @@ class FlowVersion(SQLModel, table=True):  # type: ignore[call-arg]
     data: dict | None = Field(default=None, sa_column=Column(JSON))
     version_number: int = Field(nullable=False, ge=1)
     description: str | None = Field(default=None, nullable=True, max_length=500)
-    created_at: datetime = Field(default_factory=lambda: datetime.now(timezone.utc), nullable=False, index=True)
+    created_at: datetime = Field(
+        sa_column=Column(DateTime(timezone=True), server_default=func.now(), nullable=False, index=True),
+    )
 
     # The UniqueConstraint on (flow_id, version_number) creates an implicit composite
     # btree index that also covers ORDER BY version_number DESC queries filtered by