- deploy/postgres (package dbassets) embeds the full goose chain;
RunMigrations prefers the on-disk dir (dev behavior unchanged) and falls
back to the embedded FS when the source tree is absent (single-binary
deployments per plan U10/KTD16)
- goose SetBaseFS global state reset after use
- TestRunMigrationsEmbeddedFallback verified against a throwaway isolated
pgvector container: nonexistent dir -> embedded chain -> version 78,
migration gate count agrees
