Merge a layout head with a page head, the page winning on every conflict.
The layout head is the base (brand defaults); the page head is merged on top, so same-key
metas/links (deduped by property/name/rel) and title/description from the page replace
the layout's. This is the hierarchical "layout head + page head" contract of HeadManager.
Merge a layout head with a page head, the page winning on every conflict.
The layout head is the base (brand defaults); the page head is merged on top, so same-key metas/links (deduped by
property/name/rel) and title/description from the page replace the layout's. This is the hierarchical "layout head + page head" contract of HeadManager.