feat: implement strangler-fig-demo Session 1 (backend + smoke script)

Builds the four-seam, three-write-path reference demo backend: case-framework
(seam D stand-in), legacy-backend/frontend (SQL Server, seams A/B/C targets),
and new-backend (Domain/Application/Infrastructure.*/Api implementing the
source resolver, take/release-ownership, write-through translator, and owned
assessment flow), wired together via docker-compose with a plain placeholder
frontend standing in for the Angular portal until Session 2.

All 11 Architecture.Tests pass and scripts/smoke.sh passes end-to-end against
a fresh `docker compose up`, covering acceptance criteria 1-3 and 7-22.

Fixes two real domain bugs found only once the stack ran for real: the BSN
eleven-proof checksum trivially passes all-zero digits, and the adoption
mapper silently treated a partial legacy address as absent instead of failing
loudly. Also fixes several environment-specific integration issues (rootless
Podman/SELinux bind-mount permissions, a buildah NuGet layer-caching bug,
SqlClient's invariant-globalization incompatibility, and an nginx path-prefix
mismatch for the legacy frontend).

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

new/src/New.Infrastructure.Persistence/New.Infrastructure.Persistence.csproj

@@ -0,0 +1,32 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <TargetFramework>net9.0</TargetFramework>
+    <Nullable>enable</Nullable>
+    <ImplicitUsings>enable</ImplicitUsings>
+    <InvariantGlobalization>true</InvariantGlobalization>
+    <RootNamespace>New.Infrastructure.Persistence</RootNamespace>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <ProjectReference Include="..\New.Domain\New.Domain.csproj" />
+    <ProjectReference Include="..\New.Application\New.Application.csproj" />
+  </ItemGroup>
+
+  <ItemGroup>
+    <!--
+      Npgsql provider ONLY. Microsoft.EntityFrameworkCore.SqlServer must never
+      be referenced anywhere under new/ - this boundary keeps the "new" stack
+      structurally unable to reach the legacy SQL Server engine, even in
+      principle. Enforced by Architecture.Tests rule 9.
+    -->
+    <PackageReference Include="Microsoft.EntityFrameworkCore" Version="9.0.1" />
+    <PackageReference Include="Npgsql.EntityFrameworkCore.PostgreSQL" Version="9.0.4" />
+    <PackageReference Include="Microsoft.EntityFrameworkCore.Design" Version="9.0.1">
+      <PrivateAssets>all</PrivateAssets>
+      <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
+    </PackageReference>
+    <PackageReference Include="Microsoft.Extensions.Configuration.Abstractions" Version="9.0.1" />
+  </ItemGroup>
+
+</Project>