fix(core): pass local profile dir as Chrome flag

[luochen211]

Summary

• pass local browser userDataDir as a Chrome flag instead of a chrome-launcher option
• keep chrome-launcher from converting the profile path before Node filesystem operations
• add a regression test around launchLocalChrome arguments

Fixes #1503

Tests

• pnpm --dir packages/core run build:esm && pnpm --dir packages/core exec vitest run --config vitest.esm.config.mjs dist/esm/tests/unit/launch-local-ignore-default-args.test.js
• pnpm --dir packages/core run lint
• pnpm exec prettier --check packages/core/lib/v3/launch/local.ts packages/core/tests/unit/launch-local-ignore-default-args.test.ts
• git diff --check

---

Summary by cubic

Fix local Chrome profile handling by passing --user-data-dir directly to Chrome instead of via chrome-launcher, avoiding path conversion and making local profiles work reliably. Fixes #1503.

• Bug Fixes
  • Add --user-data-dir=<path> to Chrome flags; stop sending userDataDir to chrome-launcher.
  • Add a regression test to assert the flag is used and the option is omitted.

^{Written for commit 8d04ca6. Summary will update on new commits.}

[changeset-bot]

🦋 Changeset detected

Latest commit: 8d04ca6

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 3 packages

Name	Type
@browserbasehq/stagehand	Patch
@browserbasehq/stagehand-evals	Patch
@browserbasehq/stagehand-server-v3	Patch

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[github-actions]

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Approving the latest commit mirrors it into an internal PR owned by the approver.
If new commits are pushed later, the internal PR stays open but is marked stale until someone approves the latest external commit and refreshes it.

[cubic-dev-ai]

No issues found across 3 files

Confidence score: 5/5

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

Architecture diagram

sequenceDiagram
    participant Test as Regression Test
    participant Launch as launchLocalChrome()
    participant Flags as ChromeFlags Builder
    participant Launcher as chrome-launcher

    Note over Test,Launcher: Launch flow

    Test->>Launch: call with userDataDir option
    Launch->>Flags: build chromeFlags array
    Flags->>Flags: append "--user-data-dir=<path>"
    Flags-->>Launch: chromeFlags list
    Launch->>Launcher: launch({ chromeFlags, ignoreDefaultFlags })
    Note over Launch,Launcher: userDataDir NOT passed to launcher
    Launcher->>Launcher: start Chrome with flags
    Launcher-->>Launch: browser instance

    Note over Test,Launcher: Assertion path

    Test->>Launch: getLaunchArgs() captures launcher options
    alt userDataDir option absent from launcher
        Test-->>Test: expect args.userDataDir to be undefined
    end
    alt chromeFlags contains user-data-dir
        Test-->>Test: expect "--user-data-dir=<path>" in flags
    end

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