Function diff_views 

pub fn diff_views(
    target_views: &[View],
    source_views: &[View],
    out: &mut ChangeSet,
    managed_roles: &BTreeSet<Identifier>,
)

Diff target.views (live DB) against source.views (desired).

Pairs views by QualifiedName and emits:

• ViewChange::Create for views present only in source.
• ViewChange::Drop for views present only in target.
• ViewChange::ReplaceBody when the canonical body hashes differ.
• ViewChange::SetReloption when security_barrier / security_invoker differ (independent of body changes).
• ViewChange::SetComment / ViewChange::SetColumnComment for metadata changes.
• Change::AlterObjectOwner / grant changes when applicable.

No change is emitted when target and source are byte-for-byte identical.