chore(meta): update changelog

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

CHANGELOG.md

@@ -19,6 +19,7 @@ Format based on [Keep a Changelog](https://keepachangelog.com/).
 - **Gemma naming methodology doc** (`docs/gemma-naming-methodology.md`) — preserves the corridor-aware LLM place-naming approach (sector palettes, few-shot prompting, dedup, Earth-major blocklist, deterministic fallback) as institutional knowledge after the naming pipeline's retirement
 - **Layer-1 world topography cascade** (#953, D-208/209/210) — deterministic empty-world generation in Rust: D8 priority-flood drainage (rivers/basins, ~45 ms/body after optimization), 7 geographic settlement-attractor tags, and sub-biome + terrain-modification-cost classification. The foundation the settlement-placement layer builds on
 - **Canonical 16-bit heightmaps** (#963, D-202) — every body's elevation is now a per-body 16-bit grayscale `heightmap.png` (1024×512, `sea_level` in a tEXt chunk); the old color render is renamed `reliefmap.png`. Single source of truth the generation cascade reads
+- **Deterministic generation cascade** (#952, D-224/D-200) — `SeedChain`, a single splitmix64-based seed-derivation contract descending from the master world seed with domain separation (replaces ad-hoc seed mixing); an extensible per-layer cascade harness (`run_cascade`); and a golden-seed regression test pinning Layer 0→1 output (source heightmap SHA-256 + serialized topography) so any determinism drift is caught
 
 ### Changed
 - `teammateMode` set to `auto` — teammates spawn in tmux split panes when the lead runs inside tmux, with graceful in-process fallback