feat(schema): extend systems.db for economics (#804)

Add 5 new tables: gate_links (668 bidirectional edges from star-map.json),
commodities (36 types from commodities.toml), production_chains (21
Leontief recipes), chain_inputs (52 input requirements), corp_presence
(empty, populated by future pipeline). Add currency_zone column to
star_systems (D-172), archetype columns to corporations (D-175).

New import pipeline: tooling/economy-db/import_economics.py reads
TOML/JSON source files and populates the DB. Idempotent — safe to
rerun via `make economy-db`.

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

Makefile

@@ -3,7 +3,7 @@ GODOT := $(shell command -v godot4 2>/dev/null || command -v godot 2>/dev/null)
 .PHONY: help setup build check-protocol client server game stop test lint lint-python setup-venv ci ci-client ci-server clean \
        decisions-sync decisions-coverage decisions-active decisions-orphan \
        db-backup db-install validate-content check-fact-ids setup-hooks \
-       audit atlas-verify \
+       audit atlas-verify economy-db \
        pre-pr pre-pr-lint pre-pr-build pre-pr-test pre-pr-validate pre-pr-fixtures \
        pre-pr-server pre-pr-client pre-pr-content \
        fixtures-client fixtures-gauntlet golden-diff golden-update \
@@ -53,6 +53,7 @@ help:
 	@echo "  make validate-content   Validate content YAML against schemas"
 	@echo "  make check-fact-ids    Check fact_id references against knowledge catalogs"
 	@echo "  make atlas-verify      Verify atlas proposal JSONs (all in docs/atlas/proposals/)"
+	@echo "  make economy-db        Import economics data into systems.db (TOML/JSON → SQLite)"
 	@echo "  make fixtures-client    Generate GDScript->Rust cross-encoder fixtures (#475)"
 	@echo "  make golden-diff        Show diff if golden file output has changed"
 	@echo "  make golden-update      Regenerate golden file and stage for commit"
@@ -323,6 +324,9 @@ db-backup:
 db-install:
 	@tooling/db-install
 
+economy-db:  ## Import economics data (commodities, chains, gate links) into systems.db
+	@python3 tooling/economy-db/import_economics.py
+
 # --- Decisions ---
 
 decisions-sync: