Move the localhost default off BattleNodeOptions and out of Program.cs
into an appsettings.json "BattleNode" section, and make AddBattleNode
throw at startup if the value is missing or blank. Deployments now must
set the URL explicitly, and dev keeps working via the checked-in value.
Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
Registers Serilog via SVSim.Hosting.UseSvSimSerilog("svsim-api") right
after CreateBuilder and wraps Main in try/catch/finally so a fatal
startup exception logs before CloseAndFlush.
Also updates the SVSim.Hosting extension to gate the file sink on entry
assembly rather than the ASP.NET environment name. WebApplicationFactory
sets the environment via a hook that resolves after both CreateBuilder
and the UseSerilog callback see their environment view, so
IsEnvironment("Testing") is unreliable in tests. The entry assembly
under `dotnet test` is always "testhost", which is a reliable signal.
appsettings.json grows a Serilog section mirroring the existing
Logging:LogLevel overrides; the Logging block itself is left in place
per the spec's follow-up cleanup note.
Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
