fix(content): PR #133 review — 9 remaining items resolved

Closes 9 of 10 review items (blocker 1 handled in add2507e + d78d3b59):

- decisions/economics.md: reformat D-189 §5 amendment to standard
  Amendment (YYYY-MM-DD) block pattern (review #4)
- tooling/planet-gen/sol_name_fixes.py: dedup guard + argparse
  --dry-run (reviews #5, #10a)
- tooling/planet-gen/sol_markers/earth_features.json: trim to 11
  cities with selection rationale (review #6A); user-approved
  rebalance Sydney → Lagos and London → Brussels (review #6B)
- wiki/star-systems/GJ-380/bodies/GJ380c/markers.json: 2 secondary
  features renamed to Akan/Asante register — Kesset → Nkwanta Beck,
  Holt Spur → Bosomtwe Spur (review #7)
- docs/atlas/hand-refine-log.md: Aethelred lore-migration
  documentation + see-also cross-link to refine_log_849.md
  (reviews #8, #13)
- tooling/planet-gen/refine_log_849.md: rebalance addendum
- wiki/star-systems/GJ-0/bodies/GJ0d/markers.json, server/data/
  systems.db: re-synced after rebalance

Stub depth (review blocker #2) handled via split — tracked as
follow-up ticket #861 (three-layer narrative authoring).

Final Earth cities (11): Beijing, Brussels, Cairo, Delhi, Istanbul,
Lagos, Moscow, New York, São Paulo, Singapore, Tokyo.

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

docs/atlas/hand-refine-log.md

@@ -148,6 +148,27 @@ River and ocean collisions (Rio Grande ×23 rivers, Steinbruch ×19 rivers, Ridg
 - **"Jade Harbor" city on 20 bodies:** Widespread collision in generated content. The Gemma batch used this as a fallback east_reach city name. Needs addressing in the batch or a targeted pass across east_reach bodies.
 - **"Rio Grande" river on 23 bodies:** Portuguese fallback. Fix in the south_reach naming templates or targeted pass.
 
+*See also: `tooling/planet-gen/refine_log_849.md` for cross-reference arc analysis, per-body audit metrics, and before→after delta across all 13 inhabited targets.*
+
 ---
 
 *Next refine pass: re-run `atlas_quality_analysis.py` — baseline metrics should show reduced collision counts on GJ71 and GJ144 bodies.*
+
+---
+
+## Sprint 36 — Aethelred Name Legacy (GJ251c, #849 follow-up)
+
+**Date:** 2026-04-19
+**Scope:** POI name audit — GJ251c (Renaissance, GJ 251 / Groombridge 1618)
+
+### Observation
+
+During the #849 cross-reference audit, `poi_0` on GJ251c carries the name **"Aethelred's Gate"** (kind: transit, center [123, 369]).
+
+The name is intentional. The Lattice Commission survey team that named the Tau Ceti bodies worked in a strict Latin register throughout (GJ71c Threshold: Janua; GJ71d Arden: The Rostrum, The Curia, The Decumanus; GJ71d-1 Verantis: Praetorium). One team member — Aethelred — carried an Anglo-Saxon name that didn't fit the Latin convention. When the #849 pass renamed GJ71c rivers from English institutional titles to Latin equivalents, any English-register memorial from that survey was displaced from Threshold's naming space.
+
+GJ251c (Renaissance) was surveyed by the same Commission but settled by a mixed Latin/Germanic population: its capital is "Tributarium" (Latin) and its industrial city is "Ruhr" (Germanic). The transit gate naming convention on Renaissance accommodates this mixed register — making it the natural landing point for Aethelred's memorial. Players who compare Threshold's strictly Latin rivers with Renaissance's "Aethelred's Gate" transit POI can infer the survey team's composition and the naming politics of the Lattice Commission.
+
+### No changes made
+
+`poi_0: "Aethelred's Gate"` on GJ251c — preserved as-is. No markers.json edits. No DB sync required.