.gitignore has '/data' which Windows git (case-insensitive) silently
matched '/Data/', so AppDbContext.cs was never committed and the Docker
build (Linux, case-sensitive) failed with CS0234 'Data' not found.
Renaming the directory to 'Database/' sidesteps the collision.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>