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.
Replace alpha/beta dummies with PrototypeNpcRegistry (melee/ranged/elite),
per-archetype max HP from INpcBehaviorDefinitionRegistry, and updated
server tests + Bruno smokes. Documents breaking client change for NEO-97.
Co-authored-by: Cursor <cursoragent@cursor.com>