fix(metadata): credit David Viejo as plugin maintainer

[dviejokfs]

Summary

• Replace the published template's placeholder author, Your team, with David Viejo.
• Add a regression test for the maintainer metadata consumed by the GitHub catalog.
• Keep the registry website reading the source metadata; no site-specific author override.

Evidence

Metadata-only correction; no plugin runtime behavior changes.

Command: bun test && bun run check

(pass) the published template credits its maintainer instead of placeholder metadata
(pass) registry screenshots reference real PNG assets with accessible descriptions
12 pass
0 fail
41 expect() calls
Ran 12 tests across 5 files.
$ tsc --noEmit

Publication

After merging, refresh the gotempsh/plugins catalog workflow (or wait for its scheduled refresh). The registry reads the generated catalog on demand with a 15-minute cache. This PR alone does not change the currently published catalog.