[ARI-2161] CLI → Make Agents the code owner

[revett]

Resolves ARI-2161

Problem

• Nobody owns the repo, so new pull requests, including Dependabot's weekly updates, don't request anyone's review

Changes

• Add a CODEOWNERS file that makes @team-plain/agents the owner of everything in the repo

Why

• The CLI creates knowledge sources, which the Agents team owns
• Dependabot no longer supports a reviewers setting, so CODEOWNERS is the only way to route its pull requests to a reviewer

---

Note

Low Risk
Repository metadata only; no application code or runtime behavior changes.

Overview
Adds a new .github/CODEOWNERS so @team-plain/agents is automatically requested as reviewer on pull requests for the entire repository (*).

This replaces the old Dependabot reviewers approach and ensures PRs (including Dependabot updates) get an owner now that nothing was assigned before.

^{Reviewed by Cursor Bugbot for commit 8684a60. Bugbot is set up for automated code reviews on this repo. Configure here.}

[greptile-apps]

Confidence Score: 5/5

[Low risk] Updates code ownership metadata for the repository.

The PR appears safe to merge; no concrete failure was found.

What we checked:

• Files left without an owner: The * rule covers every path. No other ownership file or narrower rule was found.

_{Reviews (1) · Last reviewed commit: "Implement" · Reviewed by Greptile}