feat: add diagnostics and telemetry runtime

tests/fixtures/diagnostics/forbidden/raw-context.ts

@@ -0,0 +1,8 @@
+export function leakSensitiveContext(telemetry: {
+  emit(eventName: string, context: Record<string, unknown>): void;
+}) {
+  telemetry.emit("api.request.failed", {
+    authorization: "Bearer secret",
+    request_body: { email: "private@example.test" },
+  });
+}