docs(decisions): file D-237 authored specialization layer + re-amend D-233

Add D-237: each inhabited system carries three authored, static (t=0),
deterministic per-system identity fields sourced from
wiki/economics/system_specialization.toml — economic_specialization
(27-value vocabulary, scale encoded in the value), cultural_specialization
(unified activity + heritage vocabulary), and dominant_faction (populate
the existing system_factions column, 8 values, lattice_commission dropped).
Authored lore wins; a deterministic-varied seed-hashed weighted draw is the
fallback for unnamed systems so they don't read identically.

Re-amend D-233 to source dominant_bulk_class x dominant_production_ubiquity
from this authored layer (heuristic becomes fallback). Groombridge encodes
as a financial_hub Specialist district with the GSH clearing house as a
D-222/D-232 landmark rather than a composite vocabulary value.

Add the specialization-layer d2 diagram (3 fields -> D-233/D-232/D-214
consumers). Produced by the system-economic-specialization workshop.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

docs/diagrams/architecture/specialization-layer.d2

@@ -0,0 +1,83 @@
+# D-237: Authored per-system specialisation layer and its consumers
+# Shows the three authored fields, their sources, and downstream generator consumers.
+
+direction: right
+
+source: "wiki/economics/\nsystem_specialization.toml" {
+  shape: document
+  style.fill: "#e8f4e8"
+}
+
+vocab: "wiki/economics/\nspecialisation_vocabulary.toml" {
+  shape: document
+  style.fill: "#e8f4e8"
+}
+
+db: "systems.db" {
+  shape: cylinder
+  style.fill: "#f0f0f0"
+
+  econ: "system_economy\n.economic_specialization"
+  cult: "system_economy\n.cultural_specialization"
+  fact: "system_factions\n.dominant_faction"
+  specvocab: "specialization_vocabulary\n(compiled reference table)"
+}
+
+fallback: "Deterministic-varied\nheuristic fallback\n(seed-hashed weighted draw\nW_ROLE=8000, W_CORP=5000,\nW_NOISE=400)" {
+  shape: hexagon
+  style.fill: "#fff3cd"
+}
+
+d233: "D-233\nEconomic block-fill\n(BulkClass × ProductionUbiquity\n→ coverage, vocabulary,\noperations surface)" {
+  shape: rectangle
+  style.fill: "#dce8f5"
+}
+
+d232: "D-232\nArchitecture-flavor\n(template pool selection\nfor corridor vs\nheritage-divergent systems)" {
+  shape: rectangle
+  style.fill: "#dce8f5"
+}
+
+d214: "D-214\nPoliticalArchetype\n(settlement spatial layout:\ncommission radial /\ncorporate campus /\ncooperative distributed)" {
+  shape: rectangle
+  style.fill: "#dce8f5"
+}
+
+d174: "D-174\nShadow economy\nintensity" {
+  shape: rectangle
+  style.fill: "#e8dce8"
+}
+
+d172: "D-172\nCurrency zone\nvalidation" {
+  shape: rectangle
+  style.fill: "#e8dce8"
+}
+
+groombridge: "Groombridge\nlandmark mechanism:\nfinancial_hub (Specialist)\n+ GSH hero-element\nvia D-222 + D-232 pin" {
+  shape: oval
+  style.fill: "#fde8cc"
+}
+
+source -> db.econ: "import_economics.py\nimport_system_specialization()" {
+  style.stroke-dash: 3
+}
+source -> db.cult: {
+  style.stroke-dash: 3
+}
+source -> db.fact: {
+  style.stroke-dash: 3
+}
+vocab -> db.specvocab: "compiled reference" {
+  style.stroke-dash: 3
+}
+
+db.econ -> d233: "primary source\n(authored wins)"
+db.econ -> fallback: "NULL → heuristic"
+fallback -> d233
+
+db.cult -> d232: "D-232 template\npool override"
+db.fact -> d214
+db.fact -> d174
+db.fact -> d172
+
+d233 -> groombridge: "Specialist district\ncharacter"