feat: count resolved incidents as acknowledged

[benbridts]

We were having issues where we saw the pagerduty_summary_incident_acknowledge_duration_sum constantly incease, even though there were no open incidents in pagerduty.

We realized this happend because an incident was resolved before it got acknowledged.

This PR makes it so that the acknowledge_duration is capped at the resolved_duration.

Tested locally:

Before

finch run --rm -ti -p 8080:8080 webdevops/pagerduty-exporter:latest --pagerduty.authtoken=$PD_TOKEN --log.level=trace
INFO starting pagerduty-exporter v25.12.1 (f9856f4; go1.25.5; by webdevops.io at 2025-12-25T11:34:58Z)
INFO {"Logger":{"Level":"trace","Format":"logfmt","Source":"","Color":"","Time":false},"PagerDuty":{"AuthTokenFile":"","MaxConnections":4,"Schedule":{"OverrideTimeframe":172800000000000,"EntryTimeframe":259200000000000,"EntryTimeFormat":"Mon, 02 Jan 15:04 MST"},"Incident":{"Statuses":["triggered","acknowledged"],"TimeFormat":"Mon, 02 Jan 15:04 MST","Limit":5000},"Teams":{"Disable":false,"Filter":null},"Summary":{"Since":2628000000000000}},"Server":{"Bind":":8080","ReadTimeout":5000000000,"WriteTimeout":10000000000},"Cache":{"Path":""},"ScrapeTime":{"General":300000000000,"MaintenanceWindow":300000000000,"Schedule":300000000000,"Service":300000000000,"Team":300000000000,"User":300000000000,"Summary":900000000000,"System":900000000000,"Live":60000000000}}
...
INFO finished metrics collection collector=Incident duration=0.992165954 nextRun=2026-01-14T16:00:18.336Z
...
INFO finished metrics collection collector=Summary duration=24.240854676 nextRun=2026-01-14T16:14:41.585Z

http localhost:8080/metrics | grep pagerduty_summary_incident_acknowledge_duration_sum
pagerduty_summary_incident_acknowledge_duration_sum{priority="",serviceID="REDACTED",urgency="high"} 1.86483893249303e+06

After

finch run --rm -ti -p 8080:8080 pagerduty-exporter:25.12.1-dirty --pagerduty.authtoken=$PD_TOKEN --log.level=trace
INFO starting pagerduty-exporter v25.12.1-dirty (f9856f4; go1.25.5; by webdevops.io at 2026-01-14T16:01:49Z)
INFO {"Logger":{"Level":"trace","Format":"logfmt","Source":"","Color":"","Time":false},"PagerDuty":{"AuthTokenFile":"","MaxConnections":4,"Schedule":{"OverrideTimeframe":172800000000000,"EntryTimeframe":259200000000000,"EntryTimeFormat":"Mon, 02 Jan 15:04 MST"},"Incident":{"Statuses":["triggered","acknowledged"],"TimeFormat":"Mon, 02 Jan 15:04 MST","Limit":5000},"Teams":{"Disable":false,"Filter":null},"Summary":{"Since":2628000000000000}},"Server":{"Bind":":8080","ReadTimeout":5000000000,"WriteTimeout":10000000000},"Cache":{"Path":""},"ScrapeTime":{"General":300000000000,"MaintenanceWindow":300000000000,"Schedule":300000000000,"Service":300000000000,"Team":300000000000,"User":300000000000,"Summary":900000000000,"System":900000000000,"Live":60000000000}}
...
INFO finished metrics collection collector=Incident duration=0.807753905 nextRun=2026-01-14T16:03:30.896Z
...
DEBUG Overwriting acknowledgedAt based on resolvedAt collector=Summary incident=REDACTED from=2026-01-14T16:02:33.892Z to=2025-12-24T02:05:28.000Z
...
INFO finished metrics collection collector=Summary duration=24.437684963 nextRun=2026-01-14T16:17:52.527Z

http localhost:8080/metrics | grep pagerduty_summary_incident_acknowledge_duration_sum
pagerduty_summary_incident_acknowledge_duration_sum{priority="",serviceID="REDACTED",urgency="high"} 404

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

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