counter metrics do not count up

[matthias-onpier]

Expected behavior (what you expected to happen):

using a counter metric, every time you add a value the counter should be increased by the value.

Actual behavior (what actually happened):

the counter metric is set to the value it should be increased. it is not counting up.

Steps to reproduce:

1. have a hook with a counter metric and set "action":"add" and "value":1
2. execute this hook every minute
3. metrics is always set to 1 and not counting up

Environment:

• Shell-operator version: v1.14.3
• Kubernetes version: v1.34.4
• Installation type (kubectl apply, helm chart, etc.): long running container started from shell-operator docker image and hook is triggered by cron config

Anything else we should know?:

This issue came up after updating from shell operator v1.6.2 to v1.14.3. with v1.6.2 the behavior was correct and the counter was counting up. Maybe this was introduced by https://github.com/flant/shell-operator/releases/tag/v1.11.0

[aspr0d]

I would like to work on this. When a hook emits a counter with action: add and no explicit group, the parser currently sets group to the hook name. Grouped batches expire all metrics in the group before re-applying, which resets counters each run. I plan to leave group empty for counter add operations so they use the non-grouped path and accumulate across runs.