pipelines inspect: --records N in-flight sample via InspectConnector stream

From PR #2587 (inspect). The v1 inspect ships the live status + per-stage view. The design's `--records N` bounded in-flight record sample (over the `InspectConnector`/`InspectProcessor` server-streams, backed by `pkg/inspector`) is deferred: it needs `InspectConnector` added to the CLI's `ConnectorService` interface + bounded stream handling + a running-pipeline-with-data integration test. Tier 2.

Start with PR #2587 and the v1 inspect implementation, then trace the CLI's ConnectorService interface to the InspectConnector and InspectProcessor server streams backed by pkg/inspector. Add bounded handling for --records N and a running-pipeline-with-data integration test; done means the CLI returns the requested in-flight sample without unbounded streaming.

Written by the indexing model from the issue text.