Security: remove auto-login demo endpoint, require password for demo_user

Implement proper demo authentication flow

refactor: Clean up and rename to Demo Account

feat: Replace complex auto-login with simple Conference Demo button

feat: switch measurements to feet, add recorder UI, and persist telemetry to Supabase

ui: rename account chooser and open list upwards to avoid viewport cutoff

perf/ui: use forest images across pages and defer Granim init

fix: remove login container animation causing upward drift on refresh

feat: complete forest theme across all pages with consistent background image

🎨 Replace garish green backgrounds with elegant neutral gradients

✨ Redesign login page with elegant glass-morphism UI

Complete UI fixes: Granim animations + location panel buttons

Fix Granim background coverage on login page + cache bust

🌲 Update to correct aerial forest background image

🎯 Add favicon to all HTML pages

✨ Implement synchronized forest road background across all pages

fix: remove invalid stretchMode property from Granim configuration

fix: resolve Granim initialization error on login page

feat: enhance UI with Granim.js animated gradient backgrounds

Complete async database operations and codebase cleanup

Clean up design system - remove emojis and create refined monochromatic palette

Implement unified modern design system

🎨 Complete UI overhaul with modern professional interface

Fix authentication redirect loop with dual cookie+header auth

fix: Replace pbkdf2_hex with pbkdf2_hmac for correct hash function

security: Remove all hardcoded passwords from codebase and documentation

feat: Update user accounts with personalized credentials

feat: Add comprehensive authentication system with user management