chore(meta): update changelog

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

CHANGELOG.md

@@ -6,7 +6,14 @@ Format based on [Keep a Changelog](https://keepachangelog.com/).
 
 ## [Unreleased]
 
+### Added
+- Tick rate scaling system (#406, D-052) — Full/Half/Paused rates with fractional accumulation, SetTickRate player action, replaces binary pause flag
+- Proximity detection and interaction verbs (#404, D-060) — compute_nearby_interactions system with Manhattan distance ranges (close ≤2, mid ≤5), context-sensitive verb computation (Talk, Observe, Examine), PersonOfInterest priority flip, NearbyInteraction in ObserverSnapshot v4
+- Content directory skeleton (#385, D-057) — district-as-atomic-pack layout with Sova Transit first district, 17 NPC stubs, 3 locations, 5 triangles, dialogue/monologue pools, factions, knowledge catalogs, enum definitions
+- Content schema definitions (#386) — 8 JSON Schema files (draft 2020-12) for district, location, npc-profile, dialogue-pool, monologue-pool, triangle, routine, fact-catalog validation
+
 ### Changed
+- ObserverSnapshot protocol bumped to v4 — adds nearby_interactions field with serde default for backward compatibility
 - Skills trimmed for CLAUDE.md deduplication — search-docs (-48%), ticket (-17%), review-pr (-35%) now reference CLAUDE.md for basics instead of repeating them
 - Review-pr reviewer profiles extracted to `references/reviewer-profiles.md` for progressive disclosure