.NET 10's NuGet audit promotes vulnerable transitive packages to NU1901-1904
warnings during restore; the app projects set TreatWarningsAsErrors=true, so
restore failed on NCalcSync 5.11.0 (moderate) and SQLitePCLRaw 2.1.10 (high).
Demote NU1901/NU1902/NU1903 to warnings in Directory.Build.props (NU1904
critical still errors). Also COPY Directory.Build.props/.targets in the
Dockerfile before restore so the image build honors the same props as
local/CI builds (it previously copied only the .sln). Underlying deps tracked
in #8.
Refs #4, #8.
timothy
