Add the R1 novelty check and scoping decision

[LightChainr]

R1 (15-state ordered serial algebra): novelty check + scoping decision

Novelty-only retrieval note + a decision memo (the ticket asks for the memo before any prose).
No manuscript draft is written.

Asset-list freshness

Every PR cited in the ticket (#511–#519, #493, #495, #387, #448, #330) is MERGED → the
merged-asset list is current. Caveat: docs/PUBLICATION-PORTFOLIO.md (the R1 rating source) is
not on main — it lives only on the still-OPEN PR #548, so the R1 "gate" is proposed, not yet
repo policy.

Novelty retrieval (cite-or-gap)

• Serial / Nakayama algebras: classified by quivers (linear Aₙ or cyclic) + relations — infinite
  family over a field, not a 15-element transformation semigroup. [LIT]
• Diagram / partition monoids: infinite families in n; idempotent-generated sectors studied, no
  15-element match. ABSTRACT_ONLY
• SmallSemi GAP census: exhaustive only to order 8 → cannot confirm/deny novelty at order 15. [LIT]
• Exact phrase "15-state ordered serial algebra": no hit. WebSearch

Conclusion: GAP (with residual-verification caveat). No prior classification of this exact
object under another name was found, but novelty is not yet positively certified — the object's
full multiplication table was not retrieved, and order-15 confirmation needs a SmallSemi-style
enumeration or a multiplication-table/Green-relations match (not done here).

Decision memo

Pursue Option B (pure finite-semigroup publication) as the fast path, in parallel with Option A.
No prior match ⇒ Option B is a plausible standalone paper pending the order-15 verification. Option A
(probability connection / obstruction theorem) stays open and is the higher-impact path; the
portfolio doc lists task 4 (= Option B comparison) as a legitimate high-value task, so the two are
not exclusive. Residual verification (GAP SmallSemi at order 15, or table match) is a pre-submission
requirement, not a blocker for drafting.

Full Matching-One repository CI has not been run for this commit.