263a41a926
After commit 589a1044e6 (parent repo) moved
local/docs/INITNSMGR-CONCURRENCY-DESIGN.md to
local/docs/legacy-obsolete-2026-07-25/, the doc reference in
bootstrap/src/initnsmgr.rs became broken. Update it to point at
the archive path so future readers can find the design rationale.
Companion to the LG Gram Round 1 parent-repo commit (same date).