feat: add telemetry for task lifecycle events (#21922)

Relates to https://github.com/coder/internal/issues/1259

Adds new database queries and telemetry collection functions to gather
task lifecycle events (pause/resume cycles, idle time) for analytics.
    
Task events track pause/resume activity, idle duration before pausing,
paused duration, and time from resume to first app status, filtered to
recent activity based on the telemetry snapshot interval.

🤖 Created with Mux (Opus 4.6).

coderd/database/queries/workspaceapps.sql

@@ -87,3 +87,4 @@ SELECT DISTINCT ON (workspace_id)
 FROM workspace_app_statuses
 WHERE workspace_id = ANY(@ids :: uuid[])
 ORDER BY workspace_id, created_at DESC;
+