- backend/app/core/config.py: Add APP_VERSION = '1.6.0' setting
- backend/app/main.py: Update health and root endpoints to show APP_VERSION
- frontend-internal/Sidebar.svelte: Add version display in sidebar footer
- frontend-client/+layout.svelte: Add version in page footer
- All endpoints now return both app_version (1.6.0) and api_version (v1)