CI: mops backend fails to compile under moc 1.4.x (M0219 implicit transient in backup@3.0.0)

[ggreif]

Summary

Adding moc 1.4.1 to the CI matrix (see branch gabor/fix-integrity-alias-count local experiment) surfaces a hard compile error in one of mops' own transitive deps:

.mops/backup@3.0.0/src/backup-canister.mo:57.2-57.113:
type error [M0219], this declaration is currently implicitly transient,
please declare it explicitly `transient`

See run: https://github.com/caffeinelabs/mops/actions/runs/24739756755/job/72375998544

Why

moc 1.4.x promoted the implicit-transient warning (previously M0244/M0243-style advisory) to a hard type error M0219. Any actor-field declaration that isn't explicitly transient or persistent-eligible needs to be annotated.

backup@3.0.0 predates this tightening and hasn't been re-released. mops' own backend/main pulls it in transitively, so the mops backend canister build fails the moment the matrix includes a moc ≥ 1.4.

Impact

• Prevents adding moc 1.4.x to CI (the whole point of my fix(integrity): dedupe packageIds when counting resolved packages (#506) #507-adjacent matrix bump, reverted for this reason).
• Any real-world mops user who has upgraded to moc 1.4+ and depends on backup transitively will also hit this.

Proposed fixes (any or all)

1. Bump backup to a version that compiles under moc 1.4 (upstream fix in backup repo, then bump the mops backend's mops.toml).
2. If backup is orphaned: vendor the one-line transient annotation fix and pin to the vendored fork.
3. Once (1) or (2) is done, re-add 1.4.1 to the CI matrix (drop-in revert of the branch commit I reverted).

Context

Discovered while preparing a small matrix bump on top of #507. That PR only touches cli/integrity.ts; the matrix-bump commit is reverted from its branch so #507 can land independently. Filing this so the upgrade path isn't lost.

[Kamirus]

this issue is misleading, there is no problem for mops users
mops canisters are simply outdated and would need to be migrated to newer moc