[Core] Add OCI artifact reuse support for ome-agent

[op109lvb]

What this PR does

Adds OCI Object Storage artifact reuse support to ome-agent replica flow.

The replica agent now:

• Writes a completion marker after a successful upload.
• Reuses an existing completed target artifact when reuse is explicitly allowed.
• Creates an active upload lock before writing to a reusable target prefix.
• Makes concurrent jobs for the same target prefix wait instead of uploading at the same time.
• Handles stale active upload locks with a configurable timeout.
• Cleans up the active upload lock after success or normal failure.
• Adds Object Storage helpers for conditional upload/delete and richer object listing metadata.

Why we need it

Multiple replication jobs can target the same OCI Object Storage artifact prefix. Without coordination, they can upload concurrently and expose partial artifacts to later consumers. The completion marker and active upload lock make reuse safe while preserving legacy behavior unless reuse is explicitly enabled by the replication job.

Fixes #

How to test

Run:

go test ./internal/ome-agent/replica ./pkg/ociobjectstore ./pkg/constants

E2E:

• Create two replication jobs targeting the same reusable OCI Object Storage prefix.
• Verify only one job uploads the artifact.
• Verify the second job waits and then reuses the completed artifact.
• Verify stale active upload lock behavior by using a short lock timeout.

Checklist

• Tests added/updated (if applicable)
• Docs updated (if applicable)
• make test passes locally