Merge Dev - Lineage-wide run inspection in the CLI

[aliroberts]

Lineage-wide run inspection in the CLI

The weco run read commands were single-run scoped — once a run had been derived, an agent (or user) couldn't see the global best, the derived branches, or the tree the way the dashboard does. This adds lineage-aware inspection on top of the existing per-run commands. No backend changes — the lineage endpoints already exist.

New - weco run overview <run-id>

The full lineage picture in one call (dashboard parity). Pass any run ID in the lineage; returns the aggregate (status, global best metric, summed steps, member counts), the global best node across all runs, the member tree (each with its derived_from branch point, per-member best, and children), and the global_step-ordered node list. Supports --plot (lineage-wide trajectory) and --include-code.

• WecoClient.list_lineage_nodes() (GET /lineages/{id}/nodes) and shared helpers resolve_lineage_id / fetch_lineage / fetch_lineage_nodes.

Changed - status / results gain --lineage to scope across all derived runs.

Per-run stays the default - fully backward compatible. Lineage rows are labelled by global_step with run:step secondary, matching the dashboard.

• show / diff: --step best now resolves the lineage-best node - the same one derive --from-step best branches from — and surfaces its run_id when it lives in a different sub-run. Added --step run-best for the best within just the queried run. (Fixes the prior inconsistency where best meant run-best here but lineage-best in derive.)