[Performance] Extremely slow loading time when calling build_sam3_image_model

I am encountering a severe performance issue where build_sam3_image_model takes approximately 5 minutes to finish loading.

Start by reproducing the approximately five-minute call to build_sam3_image_model and profile its loading path. The issue does not name files, tests, or an environment, so first identify the relevant model-loading entry points and capture baseline timings. Done means the loading delay is resolved and the improvement is verified with comparable measurements.

Written by the indexing model from the issue text.