Use SDK 10.0.203 (10.0.204 has no MCR image)

The previous pin (sdk:10.0.204) doesn't exist on MCR — only the installer
SDK uses that patch. MCR publishes band-2 images up to 10.0.203. Band 2
publishes blazor.web.js correctly (verified locally on 10.0.204), so pin
to the newest available 2xx image, 10.0.203.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

Dockerfile

@@ -2,11 +2,11 @@
 # drift; a stale/pre-GA SDK base silently drops the Blazor framework static assets
 # (blazor.web.js) from the publish manifest → 404 in production. Bump deliberately.
 #
-# SDK 10.0.300 reintroduced exactly that regression: it published an endpoints
-# manifest without blazor.web.js, so MapStaticAssets 404'd the boot script and the
-# whole app rendered static (no interactive circuit on any page). SDK 10.0.204 is
-# verified to publish blazor.web.js (physical file + manifest entry) and pairs with
-# the 10.0.8 runtime below.
+# SDK 10.0.300 (feature band 3xx) reintroduced exactly that regression: it published
+# an endpoints manifest without blazor.web.js, so MapStaticAssets 404'd the boot
+# script and the whole app rendered static (no interactive circuit on any page).
+# Feature band 2xx publishes blazor.web.js correctly (verified locally with 10.0.204);
+# MCR's newest 2xx image is 10.0.203, used below. Pairs with the 10.0.8 runtime.
 FROM mcr.microsoft.com/dotnet/aspnet:10.0.8 AS base
 WORKDIR /app
 EXPOSE 8080
@@ -15,7 +15,7 @@ RUN apt-get update \
     && apt-get install -y --no-install-recommends curl \
     && rm -rf /var/lib/apt/lists/*
 
-FROM mcr.microsoft.com/dotnet/sdk:10.0.204 AS build
+FROM mcr.microsoft.com/dotnet/sdk:10.0.203 AS build
 WORKDIR /src
 COPY ["SharepointToolbox.Web.csproj", "."]
 RUN dotnet restore