fd-knowledge-graph: warn when domain retrieval is limited

[ronsse]

Summary

Domain-anchored retrieve query-history can resolve more tables than the requested --limit. Without an explicit warning, operators may think the returned evidence covers the whole domain when it only covers the first limited table set.

Stack

• Branch: stack/domain-anchor-limit-warning
• Base: stack/retrieval-route-signal-summary
• Parent PR: fanduel/fd-knowledge-graph#10

Expected behavior

• Domain retrieval emits a graph-safe warning when resolved table anchors exceed --limit.
• The context anchors and evidence_routes use the same limited table set.
• Runbook documents the behavior so operators can increase --limit or retrieve specific tables.

Safety

The warning only reports counts. It does not expose SQL, secrets, user identifiers, or additional table properties.

Verification

• ruff check .
• pytest -q
• git diff --check