docs: point Signal & Noise links at self-hosted version

Replace all four references to the Claude public artifact URL with the
self-hosted version at eric-turner.com/memex/signal-and-noise.html plus
the offline-capable archive at docs/artifacts/signal-and-noise.html.

The Claude artifact can now be unpublished without breaking any links
in the repo. The self-hosted HTML is deployed to the Hugo site's static
directory and lives alongside the archived copy in this repo — either
can stand on its own.

README.md

@@ -103,8 +103,8 @@ keeping cross-references intact, and flagging ambiguity for review.
 ## Why each part exists
 
 Before implementing anything, the design was worked out interactively
-with Claude as a [Signal & Noise analysis of Karpathy's
-pattern](https://claude.ai/public/artifacts/0f6e1d9b-3b8c-43df-99d7-3a4328a1620c).
+with Claude as a
+[Signal & Noise analysis of Karpathy's pattern](https://eric-turner.com/memex/signal-and-noise.html).
 That analysis found seven real weaknesses in the core pattern. This
 repo exists because each weakness has a concrete mitigation — and
 every component maps directly to one:
@@ -414,20 +414,20 @@ and how to adapt for other agents).
 **Design process** — this repo was designed interactively with Claude
 as a structured Signal & Noise analysis before any code was written.
 The analysis walks through the seven real strengths and seven real
-weaknesses of the core pattern, then works through concrete mitigations
-for each weakness. Every component in this repo maps back to a specific
-mitigation identified there.
+weaknesses of Karpathy's pattern, then works through concrete
+mitigations for each weakness. Every component in this repo maps back
+to a specific mitigation identified there.
 
 - **Live interactive version**:
   [eric-turner.com/memex/signal-and-noise.html](https://eric-turner.com/memex/signal-and-noise.html)
-  (click tabs to explore pros/cons, vs RAG, use-case fits, signal
-  breakdown, and mitigations)
-- **Original Claude artifact**:
-  [The LLM Wiki — Karpathy's Pattern — Signal & Noise](https://claude.ai/public/artifacts/0f6e1d9b-3b8c-43df-99d7-3a4328a1620c)
-- **Archived copy in this repo**:
+  — click tabs to explore pros/cons, vs RAG, use-case fits, signal
+  breakdown, and mitigations
+- **Self-contained archive in this repo**:
   [`docs/artifacts/signal-and-noise.html`](docs/artifacts/signal-and-noise.html)
+  — download and open locally; works offline
 - **Condensed written version**:
   [`docs/DESIGN-RATIONALE.md`](docs/DESIGN-RATIONALE.md)
+  — every tradeoff and mitigation rendered as prose
 
 ---