Add ConnectPlain to open the DB without the custom search_path and
switch migration and CLI flows to run on that plain connection.
Wrap multi-statement goose migrations with StatementBegin/End to
ensure statements are executed atomically. Move Stripe price outbox
seeding into a dedicated stripe migration.
Add a goose migration to create core and fedwiki schemas and move
existing
domain tables using ALTER TABLE IF EXISTS. Set connection search_path to
"core, public" after successful DB ping. Update FedWiki SQL and
sqlc.yaml to
use fedwiki.sites and include db migrations for schema awareness. Add
design
docs, specs, and tasks for schema-namespacing and the migration plan.
