fix: pipeline

.github/workflows/ci.yml

@@ -20,6 +20,8 @@ env:
   IMAGE: git.greboh.dev/greboh/hearth-api
   DOTNET_NOLOGO: true
   DOTNET_CLI_TELEMETRY_OPTOUT: true
+  # The runner's job network has no working IPv6; .NET (unlike curl) does not fall back to IPv4 quickly, so NuGet hangs.
+  DOTNET_SYSTEM_NET_DISABLEIPV6: true
 
 jobs:
   build: