fix(api): make Tracing.group return Disposable

[pavelfeldman]

Summary

• Tracing.group() now returns a Disposable that calls groupEnd() on dispose
• Enables await using pattern for automatic group cleanup

[github-actions]

Test results for "MCP"

2 failed
❌ [chrome] › mcp/autowait.spec.ts:19 › racy navigation destroys context @mcp-windows-latest
❌ [firefox] › mcp/http.spec.ts:206 › http transport browser lifecycle (persistent) @mcp-macos-latest

5337 passed, 186 skipped

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Merge workflow run.

[github-actions]

Test results for "tests 1"

1 failed
❌ [playwright-test] › expect-to-pass.spec.ts:80 › should support .not predicate @macos-latest-node20

7 flaky

⚠️ [chromium-library] › library/beforeunload.spec.ts:130 › should support dismissing the dialog multiple times `@ubuntu-22.04-chromium-tip-of-tree`
⚠️ [chromium-library] › library/popup.spec.ts:261 › should not throw when click closes popup `@ubuntu-22.04-chromium-tip-of-tree`
⚠️ [chromium-library] › library/trace-viewer.spec.ts:1223 › should display language-specific locators `@chromium-ubuntu-22.04-node22`
⚠️ [firefox-library] › library/inspector/cli-codegen-3.spec.ts:224 › cli codegen › should generate frame locators (4) `@firefox-ubuntu-22.04-node20`
⚠️ [firefox-page] › page/page-emulate-media.spec.ts:144 › should keep reduced motion and color emulation after reload `@firefox-ubuntu-22.04-node20`
⚠️ [webkit-page] › page/page-autowaiting-basic.spec.ts:79 › should await form-post on click `@webkit-ubuntu-22.04-node20`
⚠️ [playwright-test] › ui-mode-test-output.spec.ts:118 › should collapse repeated console messages for test `@macos-latest-node20`

38740 passed, 845 skipped

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Merge workflow run.