Wave 7 chunk B: remove the embeddings machinery — the ladder collapses

The owner's wave-7 ruling: embeddings die entirely (git history is the
stash); clustering is birth-session derived (chunk A, 950ddfd), labels
are session names, and the prober's graph tools replace injection.

- settings: GraphSettings collapses to { enabled } — embedding,
  embeddingModel, clustering, labeling all die. Migration story: stale
  record keys are UNREAD and dropped by the sanitizer's reconstruction;
  the next graph-section PUT (replace-whole) persists the collapsed
  shape. The settings-panel GraphSection renders one master row.
- deleted: src/server/embeddings.ts (adapters, resolveEmbeddingPortFor,
  embedNewNodes, embeddingPort, embeddingModelCatalog), the
  GET /api/models/embeddings route, scripts/embed-graph.ts, tests for
  all three, and the /api/models/embeddings picker surfaces in the UI.
- prices: EMBEDDING_PRICES overlay + callCost fallback die. cost-summary:
  the embedding stage fold dies — back to three stages (extraction/
  audit/naming) per the owner ruling; historical stages.embedding spend
  in old run records is simply not displayed.
- ports: EmbeddingPort/EmbeddingResult/EmbeddingTask die. The embeddings
  LEDGER surface (readEmbeddings/writeEmbeddings + EmbeddingsLedger +
  EMBEDDINGS_FILE + graph-deletion's vector pruning) STAYS — inert data,
  kept only so graph-context.ts compiles until Teacher's pass removes
  it; the seam dies in the follow-up interlude.
- chat-handler (approved cross-lane unwiring, wave-6 precedent): the
  extraction pipeline's embedder becomes a documented no-op (nothing
  embedded, nothing spent, ledger untouched) until Teacher's pass
  removes the phase; the graph-context injection dispatch gate, the
  graphContext deps wiring, the setContextRespawn seam, and
  turn-service's triggerGraphContext are gone — injection is dead
  code pending Teacher's file deletions.
- scripts: backfill-graph/import-notes pass the same no-op embedder;
  replay-layout derives clusters from birthSessionPartition (the same
  partition the real settle uses) instead of the embeddings ledger.
- settings-body: parseGraphSettingsBody reads the master switch only —
  old-shape keys in a body are ignored, not rejected; bad shapes 400.
- next.config: the @huggingface tracing-exclusion guards die with the
  last reference.

Cross-lane flags: extraction.ts/graph-context.ts keep stale embed
comments + the embed phase until Teacher's full pass (their parallel
interlude owns those files — zero overlap kept by design);
semantic-clusters.ts + its test stay one more round (extraction.test.ts,
Teacher's file, still imports it — they delete it with the namer cases);
ChatSettings.graphContextTokens + the graph-context-control UI stay
until Teacher+UI.

Gates: tsc clean, eslint clean, 885/885 tests, build compiles.
Live-verified on the port-3004 dev tree: PUT /api/settings/graph with
dead keys collapses on write, bad shapes 400, GET reads {enabled: true},
/api/models/embeddings 404s.

tests/render-settings.test.tsx

@@ -134,37 +134,24 @@ describe("AgentSection (thin SSR)", () => {
 	});
 });
 
-describe("GraphSection — the dependency ladder", () => {
-	// Wave 6: without an embedding model the three dependent rungs are
-	// inert (dimmed, disabled, hinted) — pinned in embedding-settings.
-	// These ladder pins isolate the CHAIN logic with a model configured.
-	const MODEL: GraphSettings = { enabled: true, embeddingModel: "openai:text-embedding-3-small" };
-
-	it("defaults with a model set: all four rungs on, none disabled", () => {
-		const html = renderToStaticMarkup(<GraphSection graph={MODEL} onSectionChange={() => {}} />);
-		for (const key of ["enabled", "embedding", "clustering", "labeling"]) {
-			assert.ok(html.includes(`data-testid="graph-row-${key}"`), key);
-			assert.ok(!tagOf(html, `toggle-graph-${key}`).includes("disabled"), `${key} touchable`);
-		}
+describe("GraphSection — the collapsed master switch (wave 7)", () => {
+	// Wave 7 (owner ruling 2026-09-23): the section is the master switch
+	// ONLY — the embedding/clustering/labeling rungs and the BYOK model
+	// picker are gone (clustering is the free birth-session partition,
+	// labels ARE session names). One row, one toggle.
+	it("renders the single master-switch row", () => {
+		const html = renderToStaticMarkup(<GraphSection graph={undefined} onSectionChange={() => {}} />);
+		assert.ok(html.includes('data-testid="graph-row-enabled"'));
+		assert.ok(!html.includes("graph-row-embedding"), "the dead rungs render nothing");
+		assert.ok(!html.includes("Embedding model"), "the picker is gone");
+		assert.ok(!html.includes("graph-row-clustering"));
+		assert.ok(!html.includes("graph-row-labeling"));
+		assert.ok(tagOf(html, "toggle-graph-enabled").includes('aria-checked="true"'), "absent record = factory ON");
 	});
 
-	it("master off grays EVERY dependent (stored values persist, resolve inert)", () => {
-		const html = renderToStaticMarkup(
-			<GraphSection graph={{ ...MODEL, enabled: false, embedding: true, clustering: true, labeling: true }} onSectionChange={() => {}} />,
-		);
-		for (const key of ["embedding", "clustering", "labeling"]) {
-			assert.ok(tagOf(html, `toggle-graph-${key}`).includes("disabled"), `${key} disabled`);
-		}
-		assert.ok(!tagOf(html, "toggle-graph-enabled").includes("disabled"), "master itself stays touchable");
-	});
-
-	it("a mid-ladder break grays only what's below it", () => {
-		const html = renderToStaticMarkup(
-			<GraphSection graph={{ ...MODEL, embedding: true, clustering: false }} onSectionChange={() => {}} />,
-		);
-		assert.ok(!tagOf(html, "toggle-graph-embedding").includes("disabled"), "embedding touchable");
-		assert.ok(!tagOf(html, "toggle-graph-clustering").includes("disabled"), "clustering touchable");
-		assert.ok(tagOf(html, "toggle-graph-labeling").includes("disabled"), "labeling grayed");
+	it("a stored off record shows the switch off", () => {
+		const html = renderToStaticMarkup(<GraphSection graph={{ enabled: false }} onSectionChange={() => {}} />);
+		assert.ok(tagOf(html, "toggle-graph-enabled").includes('aria-checked="false"'));
 	});
 });