Wave 7 close-out: the embedding ledger seam dies; notes birth via mapping lines

Part 1 — the ledger + remnants interlude (master-dispatched, owner ruling
2026-09-23: nothing configures the graph beyond chat models):

- The embedding ledger surface is gone: readEmbeddings/writeEmbeddings
  ports, the EmbeddingsLedger contract, EMBEDDINGS_FILE (config, store
  impls, graphRevision source list), and graph-deletion's vector-pruning
  step. On-disk data files stay untouched (inert history).
- The extraction embedder seam dies wholesale: ExtractionPipelineDeps
  drops the embedder dep (chat-handler + backfill/import-notes stubs go
  with it), the 'embedding' phase leaves ExtractionPhase, the usage
  capture/persist helpers die, and stages.embedding leaves
  ExtractionRunUsage (historical records keep their shape — reads are
  lenient). Extraction is two stages again, like the local-embedder era.
- Consumer-less remnants: latestQuizOutcomes + QUIZ_EVENT_KINDS,
  clusterContentId, matchClusterLabelings + Community + ClusterLabeling,
  the readClusterLabels/appendClusterLabel port seams + store impls +
  LEDGER_FILES.clusterLabels. NamingRunUsage/readNamingRuns STAY
  (standing ruling — the cost pill renders historical naming spend);
  clusterHue + MIN_CLUSTER_SIZE stay (live).
- The 'labeler' role dies: BACKGROUND_MODEL_ROLES, ROLE_SLOT, ModelRole,
  the catalog pin projections, and the UI roster strings. RolePins keys
  shrink with the union.

The notes birth fallback (owner-approved 2026-09-23, surfaced by the
interlude's live smoke: production notes imports create provenance-EMPTY
nodes (importNotes passes messages: null — the file's anchor is the
mapping line), so the provenance-only birth rule left every imported
file unclustered and invisible to the prober's session list, against the
locked file-birth ruling. A provenance-empty node now births under its
FIRST mapping line's chatId (ledger order); only notes-born nodes ever
hit the fallback (chat nodes always carry provenance; a re-encountered
node's link-append re-opens the provenance rule). Deletion-safe: mapping
lines of deleted chats are stripped alongside their provenance.

Live-verified on port 3004: a fresh notes import clusters under its
src_ id with the file path as the label, end to end with no embedder.

845/845 tests, typecheck/lint/build green.
EOF
)

src/core/contracts/graph.ts

@@ -93,7 +93,8 @@ export interface NamingRunUsage {
 	/** ISO — wall-clock time of the run. */
 	at: string;
 	durationMs: number;
-	/** The labeler role's model id. */
+	/** The naming run's labeler role model id (the role died in wave 7;
+	 * the field stays as the historical record's shape). */
 	model: string;
 	/** Every billed call (usually ONE — the namer is single-submit). */
 	steps: CallUsage[];
@@ -323,43 +324,6 @@ export interface AuditResult {
 }
 
 /** The GET /api/graph payload — everything the home view's PURE renderer needs. */
-/** cluster-labels.jsonl line — one LLM-named community (vision §1,
- * DECIDED 2026-09-13). Append-only history: records are immutable, never
- * edited or deleted; dead labelings remain as history. IDENTITY is the
- * sorted member set ("core"), hashed into the id, so re-naming the same
- * community dedupes and a labeling survives graph edits as long as at
- * least half its core survives in some single community (core-survival;
- * under half → the community is renamed, splits can keep only one
- * successor). */
-/** The embedding ledger shape (config.EMBEDDINGS_FILE): vectors for
- *  EVERY embedded node, all produced by one model at one dimensionality. */
-export interface EmbeddingsLedger {
-	/** The embedding model id (e.g. the HF repo) — mismatch = stale
-	 *  vectors, the writer re-embeds everything. */
-	model: string;
-	/** Vector dimensionality (MRL-truncated on write). */
-	dim: number;
-	/** nodeId → L2-normalized vector (cosine similarity = dot product). */
-	vectors: Record<string, number[]>;
-	/** The topic partition over those vectors, computed by the SAME
-	 *  embedder run (the user-decided trigger: recluster at the end of
-	 *  every embedding batch, never per read — the agglomerative pass is
-	 *  ~1.5s at current scale). Consumers (snapshot, settle, namer) read
-	 *  this instead of recomputing. Empty when nothing is embedded. */
-	clusters: Array<{ members: string[] }>;
-	/** ISO timestamp of the last write. */
-	updatedAt: string;
-}
-
-export interface ClusterLabeling {
-	/** "clu_" + content hash of the sorted core. */
-	id: string;
-	/** The short domain label (1–4 words), e.g. "Differential forms". */
-	label: string;
-	/** The member node ids the label was minted for, sorted — the survival core. */
-	core: string[];
-	createdAt: string;
-}
 
 /** One rendered cluster in the snapshot payload (vision §1). Members are
  * node ids; the renderer draws the hull from member positions at draw