Document Variants Deltas

When introducing new code-path variants (e.g., “ForResize” vs base algorithms), comments/documentation must clearly explain:

1) The delta vs the base implementation: what changes and what stays identical. 2) The rationale for separate variants (“why”) so future refactoring can safely unify or change behavior. 3) The key algorithmic scheme (e.g., any partitionA/partitionB split) recorded once in a durable overview—then only minimal per-function notes for true differences. 4) Comment stability/quality: avoid copy-paste reiteration of base behavior, and avoid PR-specific phrasing like “This PR…”. Replace with stable TODOs or tracking-issue links.

Practical checklist:

• At the top of each new variant entry point, add a short line such as:

  // Delta vs takeByTopologyNUMADistributed: ForResize changes allocation/accounting to retain existing CPUs; overall NUMA selection & balance scoring are otherwise identical.
  

• Add one cumulative block for the whole variant family (e.g., all *ForResize functions) that explains the scheme once (split/partitioning + what feeds what).
• Remove/shorten comments that merely restate base behavior; keep only what differs.
• If the comment references the PR/release context, convert it to a stable TODO (and link to a tracking issue).

This prevents duplicated/AI-like narrative comments and ensures the codebase contains durable, maintainable documentation of “what changed” and “why it exists.”