chore: add business-platform team to CODEOWNERS [EPD-6090]

[canagno123]

Jira: EPD-6090

• Adds @panther-labs/business-platform as an additional default code owner (alongside @panther-labs/threat-research)
• Lets the Business Platform team's approvals satisfy the code-owner gate on Dependabot PRs, which our automated triage/babysit routine (windmill#1466) surfaces weekly

🤖 Generated with Claude Code

[cursor]

PR Summary

Low Risk
Only updates CODEOWNERS metadata; no application or security logic changes.

Overview
Adds @panther-labs/business-platform as a second default owner on the repo-wide * rule in .github/CODEOWNERS, alongside @panther-labs/threat-research.

Either team can now satisfy GitHub’s code-owner requirement on PRs (including Dependabot), so Business Platform approvals count without replacing the existing default owner.

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