fix: flake8 trailing blank lines

Remove trailing blank line at EOF to satisfy flake8 W391.

backend/app/api/souls_directory.py

@@ -71,4 +71,3 @@ async def get_markdown(
     except Exception as exc:
         raise HTTPException(status_code=status.HTTP_502_BAD_GATEWAY, detail=str(exc)) from exc
     return SoulsDirectoryMarkdownResponse(handle=safe_handle, slug=safe_slug, content=content)
-

backend/app/schemas/souls_directory.py

@@ -18,4 +18,3 @@ class SoulsDirectoryMarkdownResponse(BaseModel):
     handle: str
     slug: str
     content: str
-