Revert "fix(resolution): filter stale-target edges so watch sync survives FK violations (#455) (#463)"

This reverts commit 1dfaf30a8ba66a9d72b8b67c04b4eeb0866ec674.

Switching to #462's approach — a single, lower-layer filter inside
QueryBuilder.insertEdges itself instead of three filters spread across
the resolution layer. The DB-layer filter protects every caller (current
and future) automatically and doesn't depend on the queries-layer
nodeCache invalidation staying perfect. See #455 for the bug.

The CHANGELOG entry for the user-facing fix is re-added on top of #462.