feat(rule): support humanizeDuration in annotations

[andrewloux]

duration annotations currently print raw seconds. this adds humanizeDuration, so a query value of 4800 can render as 1h 20m 0s

the renderer registers Prometheus's existing HumanizeDuration helper before parsing annotation templates. prometheus/common becomes a direct dependency at its existing version

templates can use {{ $value | humanizeDuration }} or {{ humanizeDuration .Value }}. query values stay in seconds, and changing the formatted duration keeps the same alert identity

tests render complete pod summaries across minutes, hours, and days using both syntaxes. the README documents the helper and its units

validated with go vet ./..., the CI package test suite with -race -count=1, and a binary build. consumers must deploy this release before adding the helper to rule annotations