Records the lasting decision behind the #730 fix: exact-case-first
resolution, deterministic lowest-id case-insensitive fallback, and the
explicit refusal of a unique(lower(name)) constraint (collisions are
valid canonical nodes). Previously the rationale lived only in code
comments and the issue body. Raised as a blocker in the PR #733 review.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
