Resolves the CHANGELOG conflict — main and this branch each prepended a
bullet to [Unreleased] > Fixes; both are kept. Everything else auto-merged,
including src/mcp/tools.ts, which main reworked heavily for the explore
allocation/displacement work (CG-28/31/36/38) while this branch added the
`union` kind to its container sets.
Verified on the merged tree with the native kernel built: 3070 passed,
9 skipped, 0 failed.