Fix/metrics

[timmilesdw]

Overview

Replaced binary compaction metrics with more informative metrics that show actual compaction frequency and queue load by hook.

What this PR does / why we need it

Old metrics (removed):

• tasks_queue_compaction_in_queue_tasks{queue_name, task_id} - showed task count per compaction ID
• tasks_queue_compaction_reached{queue_name, task_id} - showed only 0 or 1 when reaching cap threshold

These metrics had limited value as they only indicated whether compaction threshold was reached, without showing actual queue load or compaction activity.

New metrics (added):

• tasks_queue_compaction_operations_total{queue_name, hook} - counter showing how many times compaction ran for each hook
• tasks_queue_compaction_tasks_by_hook{queue_name, hook} - gauge showing actual number of pending tasks per hook (when >20)

Why this is better:

1. Visibility into compaction frequency: The counter shows if specific hooks trigger excessive compaction operations, indicating potential performance issues
2. Real queue load: The gauge shows actual task count (not just binary 0/1), making it possible to track queue pressure and set meaningful alerts
3. Better grouping: Metrics grouped by hook name instead of task_id, making it easy to identify problematic hooks
4. Reliable values: Metrics updated every 10 seconds via queue snapshot, always showing accurate current state

Special notes for your reviewer

• Breaking change: old metrics removed, dashboards need updates
• New metrics provide better observability for queue performance monitoring