Add context-aware alt text to 36 images across 20 MDX files flagged
by mint a11y. Descriptions are derived from each image's caption and
surrounding step text. Part of fosrl/docs-v2#116.
Standardize edition-gated terminology to Enterprise Edition across docs where feature availability is described.
Add links to /self-host/enterprise-edition so users can quickly understand edition differences before enabling gated features or selecting an installer edition.