address review: expand 402 regex, fix live-auth-keys, add tests

- Add verb patterns (got/returned/received) to catch real billing errors
- Fix same broad `402` match in live-auth-keys.ts (reviewer point #3)
- Add false-positive tests for plain numeric '402' (point #1)
- Add true-positive tests for 'got a 402 from the API' etc. (point #2)

src/agents/live-auth-keys.ts

@@ -90,7 +90,11 @@ export function isAnthropicBillingError(message: string): boolean {
   if (lower.includes("billing") && lower.includes("disabled")) {
     return true;
   }
-  if (lower.includes("402")) {
+  if (
+    /(?:status|code|http|error)\s*[:=]?\s*402\b|(?:got|returned|received|a)\s+(?:a\s+)?402\b|^\s*402\s+payment/i.test(
+      lower,
+    )
+  ) {
     return true;
   }
   return false;

src/agents/pi-embedded-helpers.isbillingerrormessage.test.ts

@@ -35,6 +35,9 @@ describe("isBillingErrorMessage", () => {
       "Room 402 is available",
       "Error code 403 was returned, not 402-related",
       "The building at 402 Main Street",
+      "processed 402 records",
+      "402 items found in the database",
+      "port 402 is open",
     ];
     for (const sample of falsePositives) {
       expect(isBillingErrorMessage(sample)).toBe(false);
@@ -47,6 +50,9 @@ describe("isBillingErrorMessage", () => {
       "error code 402",
       "http 402",
       "status=402 payment required",
+      "got a 402 from the API",
+      "returned 402",
+      "received a 402 response",
     ];
     for (const sample of realErrors) {
       expect(isBillingErrorMessage(sample)).toBe(true);

src/agents/pi-embedded-helpers/errors.ts

@@ -535,7 +535,7 @@ const ERROR_PATTERNS = {
   overloaded: [/overloaded_error|"type"\s*:\s*"overloaded_error"/i, "overloaded"],
   timeout: ["timeout", "timed out", "deadline exceeded", "context deadline exceeded"],
   billing: [
-    /(?:status|code|http|error)\s*[:=]?\s*402\b|^\s*402\s+payment/i,
+    /(?:status|code|http|error)\s*[:=]?\s*402\b|(?:got|returned|received|a)\s+(?:a\s+)?402\b|^\s*402\s+payment/i,
     "payment required",
     "insufficient credits",
     "credit balance",