feat: add billing and usage domain cores

contracts/billing/core-v1.json

@@ -0,0 +1,15 @@
+{
+  "version": 1,
+  "currency": "CNY",
+  "moneyUnit": "fen",
+  "statuses": { "insufficientBalance": 402, "idempotencyConflict": 409 },
+  "idempotencyKeys": { "charge": "job-charge:{jobId}", "refund": "job-refund:{jobId}" },
+  "quote": {
+    "quantityRounding": "ceil",
+    "ruleOrder": ["reqKeySpecificity", "conditionSpecificity", "priority"],
+    "tiedWinner": "ambiguity_error",
+    "tierStandardFactors": "multiply",
+    "tierMarkupMultipliers": "maximum"
+  },
+  "exemptions": { "billingDisabled": true, "mockProvider": true, "platformSuperAdminQuota": true }
+}

contracts/usage/core-v1.json

@@ -0,0 +1,12 @@
+{
+  "version": 1,
+  "timeZone": "Asia/Shanghai",
+  "excluded": { "sources": ["api"], "providers": ["mock"] },
+  "dedupeKey": "jobId",
+  "scopes": {
+    "personal": "accountId",
+    "organization_admin": "organizationId",
+    "super_admin": "all"
+  },
+  "organizationAdminRedaction": ["accountUsername"]
+}