Saved Tree

Group a user's saved places into the geocity Country → Region → City → District tree (Pass 2), built from each canonical place's persisted ladder — NOT recomputed from Photon. Deduped by canonical place (a place saved from N reels counts once). threshold / min_top_child tune how aggressively dense buckets split (see api/utils/geocity/tree.py). Backend-only in v1.