Document the three perf-iac filter template variables (xrpl_work_item,
xrpl_branch, xrpl_node_role) in the telemetry runbook and the data-collection
reference: what they filter, their example values, and that perf-iac stamps
them as resource attributes from its own alloy pipeline (absent outside
perf comparison runs, so the filters default to All). Also record perf as a
network value.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>