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/settings.ts

@@ -45,7 +45,6 @@ export const BACKGROUND_MODEL_ROLES = [
 	"visualMaker",
 	"extractor",
 	"auditor",
-	"labeler",
 ] as const;
 
 export type BackgroundModelRole = (typeof BACKGROUND_MODEL_ROLES)[number];
@@ -64,7 +63,7 @@ export interface RoleModelOverride {
 /** The capability tiers a user can pin models into (owner-settled mapping):
  *  strong = prober + teacher (also the per-session default-teacher
  *  starting point); cheap = researcher, demo-builder, extractor, auditor,
- *  labeler; vision = visual-maker + pdf-reader. Resolution per role:
+; vision = visual-maker + pdf-reader. Resolution per role:
  *  ROLE OVERRIDE → slot → factory pin. */
 export const MODEL_SLOTS = ["strong", "cheap", "vision"] as const;
 export type ModelSlotName = (typeof MODEL_SLOTS)[number];
@@ -174,7 +173,6 @@ export const ROLE_SLOT: Readonly<Record<ModelRole, ModelSlotName>> = {
 	demoBuilder: "cheap",
 	extractor: "cheap",
 	auditor: "cheap",
-	labeler: "cheap",
 	visualMaker: "vision",
 	pdfReader: "vision",
 };