getLoginUser selected users.account_blocked, which does not exist in the
DB (nor the Drizzle schema). Every credentials authorize() call threw a
SQL error -> NextAuth CallbackRouteError -> 'error=Configuration', so no
login could ever succeed. Remove the phantom column from the query and
LoginUser interface.
Also fix all remaining biome noNonNullAssertion / noExplicitAny lint
warnings so CI's check job (biome:lint) passes and the push deploy runs.