feat: add LogsSample supplemental query, remove deprecated getDataProvider

[karl-power]

Closes #715

Summary

• Add LogsSample support — when a user runs a Builder-mode query against the configured default logs table, Grafana's Explore view now shows sample log lines beneath the metric chart. The new getSupplementaryLogsSampleQuery() method generates a SELECT *-style Logs/List query using columns from getDefaultLogsColumns(), copies and resolves hint-based filters from the original query, orders results DESC by time, and limits to 100 rows.

• Migrate getDataProvider → getSupplementaryRequest — replaces the deprecated getDataProvider() API (which returned an Observable) with getSupplementaryRequest() (which returns a modified DataQueryRequest). Grafana handles execution; the plugin only transforms the request. As part of this, refId stamping with log-volume- / logs-sample- prefixes now happens inside getSupplementaryRequest.

• Extract splitLogsVolumeFrames from queryLogsVolume — the frame-splitting logic (which turns a multi-column logs-volume response into per-level [Time, Value] frames consumable by the histogram panel) is now a pure standalone function in logs.ts. It is applied in the query() response pipeline when logs-volume targets are detected.

Video

Untitled.mov

Notes

• The logs sample table works best when default log columns are configured i.e. Otel enabled. Otherwise it doesn't know which log columns to query and falls back to whatever is queries in the timeseries (often not useful). See towards end of video where we need to add columns manually which make time series data messy.

[SpencerTorres]

super cool, thanks for getting this working 🚀