Complete Phase 7: session users, RBAC, training export, and UAT hardening.

Fix DDA dev bugs and polish from full review pass.

Full codebase audit: fix critical perf bug, security, error handling, dead code

Save full-res before image so the before/after slider works from history View

History table view, zoom, severity markers, row hover highlight, before/after thumbnails

Add Delhi zone/village dropdowns, location tracking, and project documentation

Initial commit: SatDetect satellite change detection web app