v1.5.20

• Resolve indexed writes at their full field path so later element assignments cannot corrupt earlier field reads or widen a field to its enclosing record.
• Preserve declared map value domains across aliases, branches, loops, bracket paths, guarded optionals, and placeholder refinement.
• Fence register-propagation peepholes at resolved jump targets so erased casts and non-nil assertions cannot make short-circuit results skip their consumer.
• Add regression coverage across constructor fields, assignments, keys, calls, arithmetic, concatenation, comparisons, casts, assertions, and both short-circuit arms.