Grow the database layer from a single global connection to a named
registry, so an app can use several databases at once — each with its
own dialect. add addConnection(name, conn, dialect), db(table, name),
connection(name) -> ConnectionHandle, Model.connection, plus
setDefaultConnection/connectionNames/clearConnections. Thread the
connection through Model and relations. Backward compatible (setConnection
= "default"); resolution stays lazy so building a query never throws.
Still driver-agnostic and edge-safe — no bundled driver.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Tn7UJG3uSLwPcWaKo9gHgC