CODEOWNERS: add @zxiiro to /osdc

[jeanschmidt]

Stack from ghstack (oldest at bottom):

• -> CODEOWNERS: add @zxiiro to /osdc #644
• docs: add runner-image autoupdate doc #643
• workflows: add osdc-renovate-autoapprove auto-merge gate #642
• workflows: auto-deploy merged Renovate runner-image PRs to prod #641
• scripts: add wait-for-pr-validate.py dispatcher + status poller #640
• workflows: add osdc-pr-validate dispatchable per-PR deploy validator #639
• osdc-pre-merge: doc updates and path-filter for new workflows #638
• renovate: bootstrap runner_image_tag auto-bump pipeline #637
• scripts: add validate-runner-bump.py for Renovate diff validation #636
• _osdc-deploy: add modules/ref inputs and dynamic-region aws-login action #635
• cluster-config: add runner-image-modules subcommand and just recipes #634

Impact: CODEOWNERS / OSDC reviewers
Risk: low

What

Adds @zxiiro as a co-owner of the /osdc path in CODEOWNERS, alongside
the existing @jeanschmidt and @huydhn.

Why

Acknowledges the shared on-call for OSDC and lets @zxiiro be auto-requested
on reviews for PRs touching /osdc, matching the existing ownership of
/helpers/ and /scripts/.

How

• Append @zxiiro to the /osdc line in CODEOWNERS.

Changes

• CODEOWNERS: one line modified.

Testing

• N/A — CODEOWNERS is enforced by GitHub on subsequent PRs.

Signed-off-by: Jean Schmidt contato@jschmidt.me

[malfet]

I'm not sure how this is related to any other commit in the stack, but sure