Clusters phases B+C: labeling records, the naming call, snapshot payload

Core-survival labelings (vision section 1, DECIDED 2026-09-13):
ClusterLabeling records in a new append-only ledger
(data/graph/cluster-labels.jsonl), immutable, id = clu_ + sha256 of the
sorted core so re-naming races and re-runs dedupe at the store seam.
matchClusterLabelings (core/clusters.ts, pure): a community keeps a
record's label while at least half its core survives in it; both sides
single-successor (a split keeps one name; greedy by overlap, ties to
the newer record).

The namer (src/agent/subagents/cluster-namer.ts): ONE singular cheap LLM
call (new 'labeler' role, glm-flash/low) names every new/changed
community at once, given member names + statements (capped at 12
members per cluster). refreshClusterLabels runs POST-EXTRACTION
(user-decided) from both front doors, fire-and-forget — naming failure
never fails the run; refreshes serialize behind a chain so parallel
imports never mint duplicate labels. import-notes.ts awaits
clusterNamingSettled before exit.

Payload: GraphSnapshot.clusters (>= MIN_CLUSTER_SIZE 3) joins detection
with labelings at read time — claimed clusters carry the record's label
and id; unlabeled ones carry a member-hash id and null label. Detection
is deterministic so no memo in v1 (ms at current scale; revisit at
vault scale).

Tests (372/372): matcher half-rule/split/merge/greedy/tie cases; naming
end-to-end through importNotes (one call, one record, claim on
re-refresh), naming failure non-fatal; snapshot derivation with
labeling join; 11 test pipelines now pin an explicit labeler seam.

config.ts

@@ -47,6 +47,9 @@ export const MODELS = {
 	extractor: { model: "z-ai/glm-5.3-flash", effort: "low" },
 	/** The auditor verifies evidence exists; keep it cheap. */
 	auditor: { model: "z-ai/glm-5.3-flash", effort: "low" },
+	/** Names detected communities — one singular call, given member names
+	 * + statements. Purely a labeling flourish; keep it cheap. */
+	labeler: { model: "z-ai/glm-5.3-flash", effort: "low" },
 } satisfies Record<string, ModelSpec>;
 
 export type ModelRole = keyof typeof MODELS;
@@ -71,6 +74,8 @@ export const LEDGER_FILES = {
 	events: path.join(PATHS.graph, "events.jsonl"),
 	mappings: path.join(PATHS.graph, "mappings.jsonl"),
 	sessions: path.join(PATHS.graph, "sessions.jsonl"),
+	/** LLM-named community records (contracts/graph.ts ClusterLabeling). */
+	clusterLabels: path.join(PATHS.graph, "cluster-labels.jsonl"),
 } as const;
 
 /**