fix(upgrade): keep dev on its original upgrade behaviour

The canary rollout change (#121) also affected dev nodes: with the network
`latest` symlink no longer assumed to equal the chain version, a dev node
outside test_farms during a canary would update to the symlink instead of
waiting, unlike before.

Restore dev's original behaviour: dev always follows the network `latest`
symlink (the update worker doesn't gate dev networks) and skips the
version-match check, while still honoring the safe_to_upgrade / test_farms
gate.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

Author: ashraffouda

pkg/upgrade/upgrade.go

@@ -294,17 +294,28 @@ func (u *Upgrader) update(ctx context.Context) error {
 		targetVer = chainVer.VersionLight
 	}
 
+	isDev := env.RunningMode == environment.RunningDev
+
 	// During a canary rollout (safe_to_upgrade == false) the update worker holds the
 	// network `latest` taglink back at the last GA version, so a freshly bootstrapped
 	// node comes up on GA and non-canary nodes stay put. Only nodes whose farm is in
-	// test_farms take part, and they must target the chain (canary) version directly
+	// test_farms take part, and they must target the chain (canary) version tag directly
 	// because `latest` no longer points at it.
-	if !chainVer.SafeToUpgrade && slices.Contains(testFarms, uint32(env.FarmID)) {
+	//
+	// dev keeps the original behaviour: it always follows the network `latest` symlink
+	// (the worker doesn't gate dev) and skips the version-match check below, while still
+	// honoring the safe_to_upgrade / test_farms gate.
+	if !isDev && !chainVer.SafeToUpgrade && slices.Contains(testFarms, uint32(env.FarmID)) {
 		// retarget the taglink at the chain version, keeping the repo/tags prefix
 		prefix := remote.Target[:strings.LastIndex(remote.Target, "/")+1]
 		remote.Target = prefix + targetVer
 	}
 
+	if isDev && !chainVer.SafeToUpgrade && !slices.Contains(testFarms, uint32(env.FarmID)) {
+		// dev node that is not part of the canary; wait for safe_to_upgrade (original behaviour)
+		return nil
+	}
+
 	// obviously a remote tag needs to differ from the current tag.
 	// if the remote is different, we actually run the update and exit.
 	if remote.Target == current.Target {
@@ -314,8 +325,9 @@ func (u *Upgrader) update(ctx context.Context) error {
 
 	// the resolved hub version must match the version the chain wants us to run; for a
 	// non-canary node during a canary this keeps it from moving ahead of the GA `latest`.
+	// dev skips this check to preserve its original always-follow-`latest` behaviour.
 	remoteVer := remote.Target[strings.LastIndex(remote.Target, "/")+1:]
-	if env.RunningMode != environment.RunningDev && remoteVer != targetVer {
+	if !isDev && remoteVer != targetVer {
 		// nothing to do! `latest` hasn't caught up to the chain version yet
 		return nil
 	}