lineage show silently drops results for tables shared across multiple projects instead of warning as documented

[MichalProchazkaP3]

Summary

kbagent lineage show --downstream/--upstream <table_id> (without an explicit project: prefix) silently resolves to only ONE project's copy of the table when the same table_id exists as a node in more than one project's graph (e.g. via bucket sharing/linking across layer projects). No warning is printed, and the command exits 0 with output that looks complete.

This contradicts the command's own --help text:

Table only: bucket_id.table_name (auto-resolves, warns if ambiguous)

Steps to reproduce

1. Have two projects (A, B) where a bucket is shared from A into B, so the same bucket_id.table_name exists as a lineage node in both A: and B: namespaces, and a config in project B has an actual input-mapping dependency on it that doesn't exist in project A.
2. kbagent lineage build -d <dir> -o lineage.json (with both projects synced under ).
3. kbagent lineage show -l lineage.json --downstream "bucket_id.table_name" (no project prefix).

Expected: either a warning that the table id is ambiguous across N projects, or results merged/listed per project.

Actual: returns only project A's downstream edges, silently. Project B's real dependency (confirmed to exist in the graph's edges array and reproducible when queried as `--downstream "B:bucket_id.t