Merge claude/api-image-sees-illink-pin: the API image restores with the trimmer pin

src/DodoSSH.Api/Dockerfile

@@ -2,9 +2,18 @@
 #
 #   docker build -f src/DodoSSH.Api/Dockerfile .
 #
-# Directory.Build.props, Directory.Packages.props, NuGet.config and global.json all sit at
+# Directory.Build.props, Directory.Build.targets, Directory.Packages.props, NuGet.config and
-# the root and all four are load-bearing here — central package management means a csproj
+# global.json all sit at the root and all five are load-bearing here — central package
-# alone does not name a single version, and a build that cannot see them resolves nothing.
+# management means a csproj alone does not name a single version, and a build that cannot see
+# them resolves nothing.
+#
+# Directory.Build.targets is the one that is easy to forget, because leaving it out breaks
+# nothing until the day it does: it pins the version of the trimmer the SDK adds to
+# DodoSSH.Contracts and DodoSSH.Crypto by itself (see the comment there). Without it the restore
+# below asks for whatever ILLink the image's SDK bundles, which matches the lock files only
+# until .NET ships a servicing release — and then this image fails with NU1004 while ci.yml,
+# which does see the pin, stays green. That is how it was found: sdk:10.0-noble moved to
+# 10.0.401 (ILLink 10.0.12) and this build broke with no commit touching a package.
 
 # ---------------------------------------------------------------------------------------
 # Build
@@ -26,7 +35,7 @@ WORKDIR /src
 # dependency change and by nothing else. Every project in DodoSSH.Api's reference closure
 # has to be here — restore walks ProjectReference, and a missing csproj fails the graph
 # rather than skipping a node.
-COPY global.json NuGet.config Directory.Build.props Directory.Packages.props ./
+COPY global.json NuGet.config Directory.Build.props Directory.Build.targets Directory.Packages.props ./
 COPY src/DodoSSH.Api/DodoSSH.Api.csproj                       src/DodoSSH.Api/
 COPY src/DodoSSH.Api/packages.lock.json                       src/DodoSSH.Api/
 COPY src/DodoSSH.Contracts/DodoSSH.Contracts.csproj           src/DodoSSH.Contracts/