chore: import upstream snapshot with attribution

tests/unit/pricing-constants-split.test.ts

@@ -0,0 +1,51 @@
+// Characterization of the pricing.ts split (god-file decomposition): the host became a barrel that
+// re-exports DEFAULT_PRICING (now merged from 4 semantic family files that import shared tier consts)
+// and keeps the helper functions. Pure-data move → behavior identical. Locks: public surface, the
+// spread-merge integrity, and that lookups/cost math resolve unchanged.
+import { test } from "node:test";
+import assert from "node:assert/strict";
+
+const P = await import("../../src/shared/constants/pricing.ts");
+
+test("barrel still exports DEFAULT_PRICING + supported helpers", () => {
+  for (const name of ["DEFAULT_PRICING", "getPricingForModel", "getDefaultPricing"]) {
+    assert.ok(name in P, `missing export: ${name}`);
+  }
+  assert.equal(Object.hasOwn(P, "calculateCostFromTokens"), false);
+});
+
+test("DEFAULT_PRICING merges the 4 family files; families partition all entries", async () => {
+  const merged = Object.keys((P as Record<string, object>).DEFAULT_PRICING).length;
+  const families: [string, string][] = [
+    ["oauth-subscriptions", "DEFAULT_PRICING_OAUTH"],
+    ["frontier-labs", "DEFAULT_PRICING_FRONTIER"],
+    ["inference-hosts", "DEFAULT_PRICING_INFERENCE"],
+    ["regional", "DEFAULT_PRICING_REGIONAL"],
+  ];
+  let famTotal = 0;
+  const seen = new Set<string>();
+  for (const [file, exportName] of families) {
+    const mod = await import(`../../src/shared/constants/pricing/${file}.ts`);
+    for (const k of Object.keys(mod[exportName])) {
+      assert.ok(!seen.has(k), `pricing key ${k} appears in more than one family`);
+      seen.add(k);
+      famTotal++;
+    }
+  }
+  assert.equal(merged, famTotal, "spread-merge lost/duplicated a top-level key");
+  assert.ok(merged > 25);
+});
+
+test("shared tier consts feed the parts (a known model resolves to a shared rate)", () => {
+  const pricing = (P as Record<string, (p: string, m: string) => unknown>).getPricingForModel(
+    "openai",
+    "gpt-4o"
+  );
+  assert.ok(pricing && typeof pricing === "object");
+  assert.equal(typeof (pricing as { input?: number }).input, "number");
+});
+
+test("formatCost remains re-exported from the pricing barrel", () => {
+  const fn = (P as Record<string, (value: number) => string>).formatCost;
+  assert.equal(fn(0.0123), "$0.0123");
+});