Foundation for the multi-tenant migration: adds the Family table with a
unique InviteCode, and a startup hook that bootstraps a single default
family from the FamilyCode config when the table is empty. No behavior
change yet — the table exists and is seeded but nothing reads it.
Also fixes the backend test command in CLAUDE.md: dotnet test on the
.NET 10 SDK with MTP rejects the --solution switch and positional
project args, so we now use Push-Location + --project.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Josh Rogers
7c1cfd62e6