perf: enable .NET sidecar trimming and single-file publish

- Enable PublishTrimmed with TrimMode=partial to remove unused
  framework assemblies while preserving app/SDK code safety
- Enable PublishSingleFile to bundle all managed assemblies into
  one executable (sidecar goes from 254 files to 2 files)

Sidecar shrinks from 191 MB / 254 files to 134 MB / 2 files.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

scripts/publish-sidecar.ts

@@ -56,6 +56,9 @@ await runCommand(
     'true',
     '-p:DebugType=None',
     '-p:DebugSymbols=false',
+    '-p:PublishTrimmed=true',
+    '-p:TrimMode=partial',
+    '-p:PublishSingleFile=true',
     '-o',
     outputDirectory,
   ],