Use each paired child's shape-ref directly. Resolving it through its own
component can select a different nesting level and move the child into an
earlier auto cell. Fix F134.
The regression moved column 2 to column 1 before the fix; all 3 assertions
now pass. Benchmark ratios against Phase 1e: main 10/100/1000
0.46/0.52/0.53; three levels 0.47; chain 0.51; library 0.51;
many shapes 0.49; variant switch 0.61. No regression flag.
AI-assisted-by: GPT-6
8a034be8fd