Apply Roslyn/dotnet-format fixes across NeonSprawl.Server and
NeonSprawl.Server.Tests: collection expressions, concrete helper
return types, record XML docs, logging guards, quest store refactors,
and removal of redundant usings via GlobalUsings.cs. Extend
csharp-style.md with the recurring patterns.
Primary constructor on ContractTemplateCatalog; concrete List return
types in loader parse helpers; collection spread in NormalizeBundle;
const emptyCatalog in roster gate test.
Startup loader mirrors validate_content.py E7M4 gates (roster, freeze,
cross-ref, band caps); IContractTemplateRegistry resolves templates by id.
Bruno health smoke confirms host boot after catalog validation.