Fix bug by ensuring requestable items process can see repository name/id

[rshiggin]

Description

For requestable items ead2_component_config.rb expects to see repository name at repository_ssm. We were configured to expose only repository_ssim. Added repository_ssm to solr_document.rb and ead2_component_config.rb.

Longer explanation from Claude

Component traject config indexed the repository name into repository_ssim only, while stock ArcLight indexes both
repository_ssm and repository_ssim. Arclight::SolrDocument#repository reads repository_ssm, so it returned nil for all components; repository_config (resolved by name lookup against repositories.yml) was therefore nil, and the Aeon request helpers called methods on it unguarded. Collection records were unaffected because the collection config indexes both fields — which is why the bug only surfaced on component-level pages.

Other recommendations

Claude suggest other changes in "requestable items" code. See https://mlit.atlassian.net/browse/ARC-170

Screencap of error