test: cover disabling --site-per-process default (#2202)

[seanmcguire12]

why

--site-per-process is a Stagehand local-browser default, so users need a reliable regression test that
localBrowserLaunchOptions.ignoreDefaultArgs can remove it. Refs #2193.

what changed

Added unit coverage for launchLocalChrome verifying that ignoreDefaultArgs: ["--site-per-process"] removes the Stagehand default while preserving user-provided Chromium flags such as --disable-features=site-per-process,IsolateOrigins and --renderer-process-limit=6.

test plan

• pnpm --dir packages/core exec vitest run --config vitest.esm.config.mjs dist/esm/tests/unit/launch-local-ignore-default-args.test.js
• pnpm --filter @browserbasehq/stagehand run typecheck
• pnpm exec prettier --check packages/core/tests/unit/launch-local-ignore-default-args.test.ts

---

Summary by cubic

Adds a unit test to ensure localBrowserLaunchOptions.ignoreDefaultArgs: ['--site-per-process'] disables Stagehand’s --site-per-process default in local Chrome while preserving user flags (--disable-features=site-per-process,IsolateOrigins, --renderer-process-limit=6, --remote-allow-origins=*). Refs #2193.

^{Written for commit 8dd9cbf. Summary will update on new commits.}

why

what changed

test plan

[changeset-bot]

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[cubic-dev-ai]

No issues found across 1 file

Confidence score: 5/5

• Automated review surfaced no issues in the provided summaries.
• No files require special attention.

_{Re-trigger cubic}