feat(deno): Export metrics API from Deno SDK

The metrics namespace is already exported from @sentry/core and re-exported
by @sentry/node, but was missing from the Deno SDK.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: sergical

packages/deno/src/index.ts

@@ -89,6 +89,7 @@ export {
   updateSpanName,
   wrapMcpServerWithSentry,
   featureFlagsIntegration,
+  metrics,
 } from '@sentry/core';
 
 export { DenoClient } from './client';

packages/deno/test/mod.test.ts

@@ -2,7 +2,7 @@ import type { Event } from '@sentry/core';
 import { createStackParser, nodeStackLineParser } from '@sentry/core';
 import { assertEquals } from 'https://deno.land/std@0.202.0/assert/assert_equals.ts';
 import { assertSnapshot } from 'https://deno.land/std@0.202.0/testing/snapshot.ts';
-import { DenoClient, getCurrentScope, getDefaultIntegrations } from '../build/esm/index.js';
+import { DenoClient, getCurrentScope, getDefaultIntegrations, metrics } from '../build/esm/index.js';
 import { getNormalizedEvent } from './normalize.ts';
 import { makeTestTransport } from './transport.ts';
 
@@ -74,6 +74,12 @@ Deno.test('captureMessage twice', async t => {
   await assertSnapshot(t, ev);
 });
 
+Deno.test('metrics API is exported', () => {
+  assertEquals(typeof metrics.count, 'function');
+  assertEquals(typeof metrics.gauge, 'function');
+  assertEquals(typeof metrics.distribution, 'function');
+});
+
 Deno.test('App runs without errors', async _ => {
   const cmd = new Deno.Command('deno', {
     args: ['run', '--allow-net=some-domain.com', './test/example.ts'],