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.

src/core/cost-summary.ts

@@ -55,12 +55,13 @@ export interface GraphCostSummary {
 	totalDollars: number;
 	/** Runs where EVERY stage was unpriced (totalDollars excludes them). */
 	unpricedRuns: number;
-	/** The billable pipeline stages (wave 6: the embedder became one —
-	 *  provider embeddings cost money; merger is the only free stage). */
+	/** The billable pipeline stages. (Wave 7, owner ruling 2026-09-23:
+	 *  back to three — the embedding stage is gone with the provider
+	 *  embedder; historical records' stages.embedding spend is simply not
+	 *  displayed.) */
 	stages: {
 		extraction: StageCost;
 		audit: StageCost;
-		embedding: StageCost;
 		naming: StageCost;
 	};
 	/** Newest first, capped at `recentCap` (default 10). */
@@ -115,7 +116,6 @@ function mergeTokens(into: CallUsage, steps: readonly CallUsage[]): void {
 export function graphCostSummary(input: CostSummaryInput): GraphCostSummary {
 	const extraction = emptyStage();
 	const audit = emptyStage();
-	const embedding = emptyStage();
 	const naming = emptyStage();
 	const runs: RecentRun[] = [];
 
@@ -134,25 +134,12 @@ export function graphCostSummary(input: CostSummaryInput): GraphCostSummary {
 		if (audDollars === null) audit.unpricedRuns++;
 		else audit.dollars += audDollars;
 
-		// Wave 6: the embedding tail — present only when an embedding model
-		// ran (absent stage = the run embedded nothing, never "free").
-		let embDollars: number | null = null;
-		let embSteps: CallUsage[] = [];
-		if (stages.embedding) {
-			embedding.runs++;
-			embSteps = stages.embedding.steps;
-			mergeTokens(embedding.tokens, embSteps);
-			embDollars = stageDollars(stages.embedding.model, embSteps);
-			if (embDollars === null) embedding.unpricedRuns++;
-			else embedding.dollars += embDollars;
-		}
-
 		// Run-level: null only when EVERY stage is unpriced.
-		const allStages: Array<number | null> = [extDollars, audDollars, embDollars];
+		const allStages: Array<number | null> = [extDollars, audDollars];
 		const runDollars = allStages.every((d) => d === null)
 			? null
 			: allStages.reduce<number>((a, d) => a + (d ?? 0), 0);
-		const allSteps = [...stages.extractor.steps, ...stages.auditor.steps, ...embSteps];
+		const allSteps = [...stages.extractor.steps, ...stages.auditor.steps];
 		runs.push({
 			startedAt: run.startedAt,
 			at: run.at,
@@ -195,9 +182,9 @@ export function graphCostSummary(input: CostSummaryInput): GraphCostSummary {
 	// A run is "unpriced" when it billed nothing countable at all.
 	const unpricedRuns = runs.filter((r) => r.dollars === null).length;
 	return {
-		totalDollars: extraction.dollars + audit.dollars + embedding.dollars + naming.dollars,
+		totalDollars: extraction.dollars + audit.dollars + naming.dollars,
 		unpricedRuns,
-		stages: { extraction, audit, embedding, naming },
+		stages: { extraction, audit, naming },
 		runs: capped,
 	};
 }