rate()/$__rate_interval can return no data on stat panels when the
calculated interval doesn't align with scrape points. Switch to
increase()/$__range to match the same approach used by the other
stat panels and reliably capture all errors in the selected window.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Use $__rate_interval instead of fixed 5m, sum() to aggregate across
instances, and 'or on() vector(0)' so the numerator falls back to 0
when no 5xx series exist instead of leaving the panel blank.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Counters displayed with increase() return floats due to Prometheus
interpolation. Force integer display on the three total panels.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

challenges_updated_total has a status label, so increase() alone
returns one series per status value. Wrap with sum() to collapse
all statuses into a single total for the stat panel.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Replace raw counter with increase(...[$__range]) on the three stat
panels so they reflect events within the time window chosen in Grafana
instead of the all-time cumulative value.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Add stat panels for total created/deleted/updated challenges and a
full-width timeseries showing created vs deleted per period using
increase() over $__rate_interval.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Master

See merge request !1

# Conflicts:
#   .gitlab-ci.yml