~anthropic/claude-sonnet-latest → B (65:35)

B is a substantive algorithmic refactor that replaces an O(n²) sort-based pairing scheme with a simpler linear-scan approach, preserving behavior (tests kept, semantics documented) while improving performance and reducing complex enum/sort-key machinery. A is a small, valid concurrency fix (releasing a read lock earlier to avoid writer starvation) but is narrower in scope and impact compared to B's broader design simplification with performance benefits.