#573 extension search returns null repository fields that extension info populates

Description

swamp extension search --json returns null for the repository, repositoryVerified, and repositoryVerifiedUrl fields, even for extensions that have a set and verified repository. swamp extension info --json returns the correct, populated values for the same extension. The two commands disagree on the same registry data.

Steps to reproduce

$ swamp extension search 'mongodb' --json \
  | jq '.extensions[] | select(.name=="@keeb/mongodb") | {repository, repositoryVerified, repositoryVerifiedUrl}'
{
  "repository": null,
  "repositoryVerified": null,
  "repositoryVerifiedUrl": null
}

$ swamp extension info @keeb/mongodb --json \
  | jq '{repository, repositoryVerified, repositoryVerifiedUrl}'
{
  "repository": "https://github.com/keeb/swamp-mongodb",
  "repositoryVerified": true,
  "repositoryVerifiedUrl": "https://github.com/keeb/swamp-mongodb"
}

Expected

extension search returns the same repository* values as extension info for a given extension (or, if search intentionally omits them, that should be documented and the fields left out rather than returned as null).

Actual

extension search --json always returns null for repository, repositoryVerified, and repositoryVerifiedUrl, regardless of whether the extension actually has a verified repo. extension info --json populates them correctly. Reproduced across multiple extensions.

Impact

Any tooling that reads an extension's source repository from extension search --json gets null and may wrongly conclude the extension has no repo. The repo link is only reachable via extension info.

Environment

swamp dev build 20260206.200442.0-sha. (latest)