fix(build): refresh the dependency manifest after #733

[mparrett]

main is red at 1ef26f9. check-generated-manifest reports three outputs stale and both generated-artifacts and build fail:

pkg/ir/op_generated.go
pkg/rt/core/ir/data/generated.lg
pkg/rt/ir_bridge_generated.go
ERROR: dependency manifest stale or check errored — run 'make generate'.

The run before it, a9936cd (#741), was green.

Cause

#733 edits scripts/generate.lg, which #641's manifest declares as the generator for those three outputs, so its recorded hash no longer matches the tree.

#733's own checks were green when it merged because they last ran against a pre-#641 base, and GitHub does not re-run a PR when its base moves. The badge outlived the base it was measured on. This is not a defect in #733 — the same trap is armed for every branch that predates #641 and touches a declared input.

Fix

make generate. Only the manifest and its digest change; no generated output content moves, which is the expected shape when the inputs are restaged but the outputs were already in lockstep.

Verification

• Reproduced at 1ef26f9 in a clean worktree before the change.
• make check-generated passes after it, including core_compiled.lgb bundle lockstep and core_go_lowered/ native dispatch under -tags gogen_ir.

Fallout worth knowing

Branches rebased onto main between #641 and this fix regenerated against the broken manifest and will need make generate re-run: #727 and #692 are both in that window. #683 also edits scripts/generate.lg and currently shows green from a stale base, so it is the same trap as #733 and should be re-run before it is merged rather than after.

#747 tracks the underlying gap. The gate does its job, but only after the merge: nothing forces a re-run between approval and merge, so a green badge over a moved base is exactly what let this land.

[mparrett]

@nnunley when you get a moment — could you take a look? main is red right now and this is the fix, so I'd rather not merge it on my own approval.

It is two files: make generate restages generated.manifest and its digest. No generated output content moves, which is the shape you would expect when the inputs are restaged but the outputs were already in lockstep. All 14 checks are green.

To be clear about the cause, this is not a defect in #733. It edits scripts/generate.lg, which #641's manifest declares as the generator for op_generated.go, core/ir/data/generated.lg and ir_bridge_generated.go, so its recorded hash stopped matching the tree. #733's own checks were green because they last ran against a pre-#641 base, and GitHub does not re-run a PR when its base moves — so the badge outlived the base it was measured on. The same trap is armed for every branch that predates #641 and touches a declared input; #733 just got there first. #683 edits the same file and is sitting on green from a stale base right now.

#747 has the broader thread, including the bit I would value your read on most: whether generated.manifest should get its own merge driver at all, given it carries output-readiness records and a driver regenerating it mid-merge could assert outputs are ready that were never rebuilt. That felt like your call rather than a patch from me. #748 is only the narrow half — making Compute parse before it hashes, so the sums driver can no longer mint a clean digest over a manifest still holding conflict markers.

No rush on those two. This one is just to get main green again.