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.
Add IPlayerGigProgressionStore (in-memory + Postgres V007), GET
/gig-progression snapshot, and CombatDefeatGigXpGrant on cast accept
when targetDefeated — 25 XP to breach, outside E2.M2 skill XP.
Includes tests, Bruno, README, manual QA, and plan reconciliation.