Fix Bokeh _pending_writes error by deferring on_change work; guard slider access against stale sessions

Remove GT brain pre-fill on feature selection — only load when image is selected

Move cortical profile render to background thread and cache KDTree IDW weights

Refactor: split panels into pure logic + UI layers

Parallelize image loading, add thumbnail cache, and 3-phase search

Sort by CLIP×φ, per-feature λ input, brain MEI sidecar support, gallery in UI

Switch to modular explorer package (scripts/explorer/)