Derived embedding-readiness of a resource (issue #299, Phase 4). Computed — never a stored column —
from the resource's current chunks plus its embed-job state (design §8), surfaced on
[super::resource_view::ResourceView] as the embedding-status section (B1: it rode the MCP
response envelope before the section did) so a caller can tell whether semantic (vector) search
will find a just-created resource yet. FTS is always immediate; only the vector is
eventually-consistent under async embed.