Address PR #2 review comment — the save format rewrite needed a constitution/spec amendment. - DESIGN.md: decisions log entry for serde JSON save format - spec/ROADMAP.md: item #12 marked DONE, conflict flags updated, suggested first wave revised (save.rs no longer the bottleneck) - knowledge/architecture.md: save format section rewritten for serde - knowledge/sim-mechanics.md: save format section rewritten for serde - DEVLOG.md: entry for this amendment Defense: Player contract continuity clause — serde JSON with a version field is the concrete expression of "saves survive updates: formats are versioned and migrated, never abandoned." The hand-rolled format was a maintenance bottleneck every feature fought; eliminating it closes ROADMAP #12 and removes the save format as a parallel-agent conflict surface. 👾 Generated with [Letta Code](https://letta.com) Co-Authored-By: Letta Code <noreply@letta.com>