fix: use model_validate instead of from_orm for FirmwareEntryResponse

Changed all FirmwareEntryResponse conversions from .from_orm() to
.model_validate() for better error handling and Pydantic v2 compatibility.

Also added default None values to Optional fields in FirmwareEntryResponse
to ensure proper serialization when fields are null.

Fixes 500 errors when retrieving firmware entries from database.

Co-Authored-By: Claude Haiku 4.5 <noreply@anthropic.com>

Author: code-root

backend/api/routes/firmware_route.py

@@ -109,15 +109,15 @@ class FirmwareEntryResponse(BaseModel):
     source: str
     device_model: str
     sales_code: str
-    ap_version: Optional[str]
-    csc_version: Optional[str]
-    package_variant: Optional[str]
-    country: Optional[str]
-    language: Optional[str]
-    filename: Optional[str]
+    ap_version: Optional[str] = None
+    csc_version: Optional[str] = None
+    package_variant: Optional[str] = None
+    country: Optional[str] = None
+    language: Optional[str] = None
+    filename: Optional[str] = None
     size_bytes: int
-    local_path: Optional[str]
-    notes: Optional[str]
+    local_path: Optional[str] = None
+    notes: Optional[str] = None
     created_at: datetime
     updated_at: datetime
 
@@ -202,7 +202,7 @@ def upload_firmware_file(
         existing.local_path = str(dest_path)
         db.commit()
         db.refresh(existing)
-        return FirmwareEntryResponse.from_orm(existing)
+        return FirmwareEntryResponse.model_validate(existing)
 
     # Create new entry
     entry = FirmwareEntry(
@@ -220,7 +220,7 @@ def upload_firmware_file(
     db.commit()
     db.refresh(entry)
 
-    return FirmwareEntryResponse.from_orm(entry)
+    return FirmwareEntryResponse.model_validate(entry)
 
 
 @router.post("/download")
@@ -342,7 +342,7 @@ def list_firmware_entries(
         query = query.filter(FirmwareEntry.sales_code == csc)
 
     entries = query.order_by(FirmwareEntry.created_at.desc()).all()
-    return [FirmwareEntryResponse.from_orm(e) for e in entries]
+    return [FirmwareEntryResponse.model_validate(e) for e in entries]
 
 
 @router.post("/entries")
@@ -383,7 +383,7 @@ def create_firmware_entry(
     db.add(entry)
     db.commit()
     db.refresh(entry)
-    return FirmwareEntryResponse.from_orm(entry)
+    return FirmwareEntryResponse.model_validate(entry)
 
 
 @router.put("/entries/{entry_id}")
@@ -411,7 +411,7 @@ def update_firmware_entry(
 
     db.commit()
     db.refresh(entry)
-    return FirmwareEntryResponse.from_orm(entry)
+    return FirmwareEntryResponse.model_validate(entry)
 
 
 @router.delete("/entries/{entry_id}")