Release 1.0.2

Release 1.0.2 is a docs-only patch. It retains the stack versions from release 1.0.1: Self-Managed 1.0.1, Compute Plane 1.0.0, and Observability 1.0.0. No stack upgrade is required.

Place Image Mirroring beside the Artifact Manifest and restore its links.
Simplify the Documentation Archive introduction under Legacy.
Wait for replacement OpenBao pods to exist before checking readiness in upgrade instructions, and clarify the final pod status check.

See the release 1.0.1 notes for changes to the stacks.