Every service builds with `context: ..`, and Docker only consults the
.dockerignore at the context root — the copies under frontend/ and backend/
never applied, so the host's dist/, node_modules/ and caches were shipped
into each build context.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01CB8uwHkH52qxLxAkGN4gTo
