fix(browser): provision cloud browsers through V4

[MagMueller]

Issue for this PR

Closes #159

Type of change

• Bug fix
• New feature
• Refactor / code improvement
• Documentation

What does this PR do?

It moves the embedded browser-execute skill's Cloud browser create and stop examples from /api/v3 to /api/v4, links the V4 OpenAPI, and adds a regression check for the materialized skill.

How did you verify your code works?

• bun test test/skills.test.ts
• bun typecheck
• targeted Oxlint
• Browser Use V4 OpenAPI checked for the create and stop contract

The full package run still has its existing cache-busted workspace import failure under Bun 1.3.14; this patch does not touch that test or import path.

Screenshots / recordings

Not a UI change.

Checklist

• I have tested my changes locally
• I have not included unrelated changes in this PR

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Summary by cubic

Updates the embedded browser-execute skill in bcode-browser to provision and stop cloud browsers via the V4 API instead of the deprecated V3 endpoints. Points the docs link to the V4 OpenAPI and adds regression assertions so the materialized skill no longer references V3.

^{Written for commit 9651c9f. Summary will update on new commits.}

[cubic-dev-ai]

No issues found across 2 files

_{Re-trigger cubic}