Add 3D building analysis: shadow-based height/stories estimation and construction stage classification

Code review fixes: SSIM stability, symmetric CLAHE, confidence scoring, KMeans perf, auth hardening, remove debug endpoint

Add forgot password flow and password visibility toggle

Add detailed error logging to register/login endpoints

Fix: writable data dir for HF Spaces, pin bcrypt 4.0.1

Fix: add checkfirst=True for table creation, use 1 worker

Initial commit: SatDetect satellite change detection web app