fix: sanitize oversized image payloads

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

@@ -23,5 +23,10 @@ describe("isCloudCodeAssistFormatError", () => {
   });
   it("ignores unrelated errors", () => {
     expect(isCloudCodeAssistFormatError("rate limit exceeded")).toBe(false);
+    expect(
+      isCloudCodeAssistFormatError(
+        "400 {\"type\":\"error\",\"error\":{\"type\":\"invalid_request_error\",\"message\":\"messages.84.content.1.image.source.base64.data: At least one of the image dimensions exceed max allowed size for many-image requests: 2000 pixels\"}}",
+      ),
+    ).toBe(false);
   });
 });