Eight entities (fact, fact contradiction, morning-card seen, wiki hot
cache / relation / transformation / transformation run / image caption
cache) declared IdType.AUTO while their PostgreSQL-compatible migrations
define the primary key as a plain BIGINT with no identity default.
MyBatis-Plus omits the id column from the generated INSERT under AUTO,
so every insert fails with a NOT NULL violation on those databases —
silently on paths that only log a warning. Switch them to snowflake
ASSIGN_ID, which works on all dialects since auto-increment columns
accept explicit values. Add a parameterized contract test pinning the
id strategy for all eight entities.