MySQL Boolean native type is inexpressible: `@db.TinyInt` not allowed on Boolean fields

[ymc9]

Problem

On the MySQL connector, Prisma's canonical native type for Boolean fields is @db.TinyInt(1) — and Prisma rejects @db.Boolean on MySQL (P1012: Native type Boolean is not supported for mysql connector, verified with Prisma 6.19).

ZModel has the restriction inverted: the stdlib declares @db.TinyInt with @@@targetField([IntField]), so it cannot be applied to Boolean fields, while @db.Boolean is accepted.

model M {
    id Int     @id
    b  Boolean @db.TinyInt(1) // ZModel error: attribute "@db.TinyInt" cannot be used on this type of field
    b2 Boolean @db.Boolean    // ZModel accepts — but Prisma rejects this on MySQL
}

As a result the MySQL Boolean native type is not expressible in the ZModel/Prisma common subset, which breaks porting Prisma schemas that use Boolean @db.TinyInt(1) (a common shape, since it's what prisma db pull emits).

Expected

@db.TinyInt should also target BooleanField (stdlib: add BooleanField to its @@@targetField list), matching Prisma's MySQL connector.

Context

Found while building the Prisma physical-schema parity test suite for the native migration engine — the exhaustive MySQL native-type case documents this gap in a comment. The default Boolean → tinyint(1) mapping (no native type attribute) is unaffected and already matches Prisma.