Add JesperSchulz to every CODEOWNERS rule

[Jesper Schulz-Wedde (JesperSchulz)]

Summary

Append @jesperschulz to the six CODEOWNERS domain rules for events, performance, privacy, security, testing, and upgrade. All 10 active rules now explicitly include that account; all existing domain experts, patterns, comments, ordering, and whitespace are preserved.

Narrower domain patterns override the broad /microsoft/ entry. Explicitly listing @jesperschulz alongside the domain experts permits his code-owner approval on other contributors' PRs without removing those experts. This change grants no admin privileges, push permissions, or self-approval powers, and does not alter branch protections or other policies.

Verification

• Compared against current main; the only changed path is root CODEOWNERS.
• Confirmed all 10 active ownership rules include @jesperschulz case-insensitively.
• Verified exactly the six expected domain rules changed, with no existing owner or pattern removed and all comments, ordering, whitespace, and line endings preserved.
• git diff --check passed; the worktree is clean.

Pushed commit: b5ddd3d9abd9a8977c92c15de462edebb8a6dca0.