refactor(saves): simplify SaveSchema construction with model_validate

Add model_validator to SaveSchema that safely handles SQLAlchemy lazy
relationships by checking inspect(obj).unloaded before attribute access.
This allows direct use of model_validate(orm_obj) instead of manually
building a dict and excluding device_syncs.

backend/endpoints/responses/assets.py

@@ -1,4 +1,9 @@
 from datetime import datetime
+from typing import Any
+
+from pydantic import model_validator
+from sqlalchemy import inspect
+from sqlalchemy.exc import InvalidRequestError
 
 from .base import BaseModel
 from .device import DeviceSyncSchema
@@ -37,6 +42,25 @@ class SaveSchema(BaseAsset):
     screenshot: ScreenshotSchema | None
     device_syncs: list[DeviceSyncSchema] = []
 
+    @model_validator(mode="before")
+    @classmethod
+    def handle_lazy_relationships(cls, data: Any) -> Any:
+        if isinstance(data, dict):
+            return data
+        try:
+            state = inspect(data)
+        except Exception:
+            return data
+        result = {}
+        for field_name in cls.model_fields:
+            if field_name in state.unloaded:
+                continue
+            try:
+                result[field_name] = getattr(data, field_name)
+            except InvalidRequestError:
+                continue
+        return result
+
 
 class SlotSummarySchema(BaseModel):
     slot: str | None

backend/endpoints/saves.py

@@ -35,7 +35,7 @@ def _build_save_schema(
     device: Device | None = None,
     sync: DeviceSaveSync | None = None,
 ) -> SaveSchema:
-    device_syncs: list[DeviceSyncSchema] = []
+    save_schema = SaveSchema.model_validate(save)
 
     if device:
         if sync:
@@ -47,7 +47,7 @@ def _build_save_schema(
             last_synced = save.updated_at
             is_untracked = False
 
-        device_syncs.append(
+        save_schema.device_syncs = [
             DeviceSyncSchema(
                 device_id=device.id,
                 device_name=device.name,
@@ -55,15 +55,9 @@ def _build_save_schema(
                 is_untracked=is_untracked,
                 is_current=is_current,
             )
-        )
+        ]
 
-    save_data = {
-        key: getattr(save, key)
-        for key in SaveSchema.model_fields
-        if key != "device_syncs" and hasattr(save, key)
-    }
-    save_data["device_syncs"] = device_syncs
-    return SaveSchema.model_validate(save_data)
+    return save_schema
 
 
 DATETIME_TAG_PATTERN = re.compile(r" \[\d{4}-\d{2}-\d{2}_\d{2}-\d{2}-\d{2}\]")