Update basics.md for the new loading indicators, 3D WebGL context-loss recovery, and the corrected movement-visibility rule (span overlap plus any catalogued artist). Refresh remaining docs and config for the current dev-first workflow and npm script names.
Co-authored-by: Cursor <cursoragent@cursor.com>
Default all day-to-day work to gallery_dev and devgallery; add Cursor rule and update docs, env examples, and deploy guide for scheduled prod promotion.