feat(google-cloud-serverless)!: Use grpc span op for GCP gRPC calls

The service suffix fragmented grouping and was unbounded for non-
`googleapis.com` service paths. Service identity moves to `rpc.service`,
with `rpc.system.name` and `rpc.method` added alongside.

Ref: JS-3105

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

Author: msonnb

packages/google-cloud-serverless/package.json

@@ -41,6 +41,7 @@
     "access": "public"
   },
   "dependencies": {
+    "@sentry/conventions": "^0.16.0",
     "@sentry/core": "10.67.0",
     "@sentry/node": "10.67.0"
   },

packages/google-cloud-serverless/src/integrations/google-cloud-grpc.ts

@@ -1,3 +1,5 @@
+import { RPC_METHOD, RPC_SERVICE, RPC_SYSTEM_NAME } from '@sentry/conventions/attributes';
+import { FAAS_GRPC_SPAN_OP } from '@sentry/conventions/op';
 import type { Client, IntegrationFn } from '@sentry/core';
 import { defineIntegration, fill, getClient, SEMANTIC_ATTRIBUTE_SENTRY_ORIGIN } from '@sentry/core';
 import { startInactiveSpan } from '@sentry/node';
@@ -106,9 +108,12 @@ export function fillGrpcFunction(stub: Stub, serviceIdentifier: string, methodNa
         const span = startInactiveSpan({
           name: `${callType} ${methodName}`,
           onlyIfParent: true,
-          op: `grpc.${serviceIdentifier}`,
+          op: FAAS_GRPC_SPAN_OP,
           attributes: {
             [SEMANTIC_ATTRIBUTE_SENTRY_ORIGIN]: 'auto.grpc.serverless',
+            [RPC_SYSTEM_NAME]: 'grpc',
+            [RPC_SERVICE]: serviceIdentifier,
+            [RPC_METHOD]: methodName,
           },
         });
         ret.on('status', () => {

packages/google-cloud-serverless/test/integrations/google-cloud-grpc.test.ts

@@ -142,9 +142,12 @@ describe('GoogleCloudGrpc tracing', () => {
       expect(mockStartInactiveSpan).toHaveBeenCalledWith({
         name: 'unary call unaryMethod',
         onlyIfParent: true,
-        op: 'grpc.test-service',
+        op: 'grpc',
         attributes: {
           [SEMANTIC_ATTRIBUTE_SENTRY_ORIGIN]: 'auto.grpc.serverless',
+          'rpc.system.name': 'grpc',
+          'rpc.service': 'test-service',
+          'rpc.method': 'unaryMethod',
         },
       });
     });