fix: return promoted default state from project create API

When add_project promotes a new project because the configured default is missing from the database, return the persisted default flag instead of echoing the request flag.

Signed-off-by: rudi193-cmd <rudi193@gmail.com>
Co-authored-by: Cursor <cursoragent@cursor.com>

src/basic_memory/api/v2/routers/project_router.py

@@ -193,7 +193,7 @@ async def add_project(
         return ProjectStatusResponse(  # pyright: ignore [reportCallIssue]
             message=f"Project '{new_project.name}' added successfully",
             status="success",
-            default=project_data.set_default,
+            default=new_project.is_default or False,
             new_project=ProjectItem(
                 id=new_project.id,
                 external_id=new_project.external_id,