fix(catalog): finish CLI parity and retire legacy add modal

[Dumbris]

Remaining low-priority work from PR #1400:

• Keep offline CLI catalog search --json and catalog show --json aligned with REST by including added_server_name when the CLI can identify one unique installed server; add focused tests. (ZCode: glm:backend.1; accepted by the current PR's REST/Web/macOS scope.)
• Remove the unreferenced AddServerModal.vue and retire or migrate its modal-specific tests, preserving meaningful coverage for shared manual-add and import behavior. (Spec 109 T108a.)
• Link Spec 109 T108a to this follow-up issue.

Both items are low priority and do not block the catalog-first user flows shipped in #1400.