Moved the economy onto resources and surfaced each building's material bill

Rebalanced the resource rules so nothing is priced primarily in money: steel, electricity and high-tech lead every construction bill, chip foundries are seeded everywhere instead of being hand-placed, and cities open with stores of steel and high-tech. City building rows now lead with the resource bill and keep the money as an aside, and the region's resources expand into the buildings that demand them. Pulled the graph and cost maths into a framework-free shared/economy_graph.js, quoted currency through one helper, and gave every data table the same striping and row highlight.

client/js/devlog_data.js

@@ -1,6 +1,12 @@
 // Generated by scripts/generate-devlog.js from `git log`; do not edit.
 // The pre-commit hook refreshes it so the main menu shows the latest commits.
 export const DEVLOG = [
+  {
+    "hash": "1324128",
+    "date": "2026-09-22",
+    "subject": "Showed idle trade routes and flagged migrant flows on the economic maps",
+    "body": "The delivery graph now ships every route the viewer's own storage nodes could trade over, not just the legs that ran, and keeps exports as well as imports so goods leaving the nation appear. The map draws the idle routes grey beneath the active white legs, with a key entry for them.\n\nThe population map replaces its bare flow arrows with the arrows plus a disc textured with the origin nation's flag drifting from city to city, mirroring the merchandise that rides the trade graph."
+  },
   {
     "hash": "aa726ff",
     "date": "2026-09-22",
@@ -54,11 +60,5 @@ export const DEVLOG = [
     "date": "2026-09-22",
     "subject": "Started a famine when a region's food runs out",
     "body": ""
-  },
-  {
-    "hash": "b6287d7",
-    "date": "2026-09-22",
-    "subject": "Replaced the GDP tax with national sales and tariff taxes",
-    "body": ""
   }
 ];