history+workplan: CoreArchitectureBlueprint review; SHARD-WP-0005 hardening

Records the critical review (history/260615-...) and establishes SHARD-WP-0005
to fold its findings (A-1, B-1..B-3, C-1..C-3, D-1..D-4) into the blueprint:
correctness (state re-frame, identity/equivalence split, consistency model),
scale (incremental-first union, equivalence indexing, cache invalidation),
elegance (orthogonal spectra, layered provenance, common-case projection,
policy module), security/history scaling, and a known-open-problems section.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

history/README.md

@@ -1,8 +1,17 @@
 # history/
 
-Archived material that is no longer needed for daily work but should be kept.
+Archived material and the project's **meta-history**: finished/canceled workplans kept for
+the record, plus durable **reviews, critical assessments, and decision records** — the
+reasoning behind the specs, captured at a point in time.
 
-Use a `yymmdd-` prefix when archiving files or directories. Content here is
-**out of scope** for regular tasks — consult only for research or diagnostics.
+Use a `yymmdd-` prefix. Archived material is **out of scope** for regular tasks (consult only
+for research or diagnostics); assessment/review records are point-in-time and may seed active
+workplans, but are not edited after the fact — supersede with a new dated record and link back.
 
-Finished or canceled workplans from `workplans/` are archived here.
+Distinct from the **coordination journal** (a runtime Git-backed record of *content* change
+flows inside an information space, an INTENT domain concept); `history/` is the *project's own*
+design evolution.
+
+| Date | Record | Subject |
+|------|--------|---------|
+| 2026-06-15 | `260615-core-architecture-blueprint-review.md` | Critical review of `spec/CoreArchitectureBlueprint.md` (commit 9b5b393); inputs to `SHARD-WP-0005` |