Replace .ToArray() with collection spread, simplify single-statement await using blocks, use Lock for Postgres schema gates, and document IDE0063/IDE0305/IDE0330/CA1859 conventions in csharp-style.md.
Add V004 perk tables, in-memory/Postgres stores, PerkUnlockEngine (tier-1 branch pick, path-auto tier-2 unlocks), level-up hook in skill XP grants, and AAA tests. Bruno docs note internal perk reevaluation on level-up (HTTP in NEO-48).