* [BugFix] Preserve invariant store scalarization
Classify vectorization constraints explicitly so broadcast loads, memory accesses, local accesses, and semantic scalarization requirements cannot be conflated by scope-based bucketing.
* [Refactor] Preserve vectorization planner diagnostics
Move the original strategy rationale into the new classification helpers and retain the established verbose summary and strategy log messages while adding separate constraint details.
* [Docs] Restore vectorization strategy overview
Chaofan Lin
cd57a840a1