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

Fix HF metadata: use valid colorTo value

Add Hugging Face Spaces support (Docker, port 7860, non-root user)

Initial commit: SatDetect satellite change detection web app