wave 7: the prober reads its map — graph-context injection dies whole

The owner's zero-configuration ruling (2026-09-23): nothing configures
the graph beyond chat models. The prior-knowledge injection — its budget
dial, its runner, its marker part, its dock/dispatch entries — is
removed across all bands; the prober now reads the learner's persistent
knowledge map on demand through two gated tools instead:

- list_sessions: every birth session, names + kinds + counts + dates
  (graphSessionIndex, Platform's core seam)
- list_propositions(session): what was born there + the session's own
  latest understanding level + that evaluation's date
  (graphSessionPropositions) — names/levels/dating ONLY, no statement
  text (owner ruling: the map's organization is the prober's business,
  its prose is not)

Registered via createProberTools when chat-handler passes graphStore
(the graphToolsEnabled gate decided server-side, per-turn fresh); the
prober doctrine gains the map-review nudge at session start.

Also: runner's JobKind special-casing collapses (KIND_ROLE/KIND_RUNNERS
are plain records again), semantic-clusters.ts dies with its test, the
embedder dep's doc tells the wave-7 stub story, and ports.ts's
readClusterLabels/readNamingRuns surface stays untouched for Platform's
ledger-port interlude.

848/848 tests, typecheck/lint/build green.

src/core/graph.ts

@@ -399,11 +399,10 @@ const QUIZ_EVENT_KINDS: ReadonlySet<string> = new Set(["correct", "miss", "dont-
 /**
  * The latest quiz outcome per node — a raw EVENT FACT, not a node state
  * (the transitional node-state classes were removed 2026-09-08: nothing
- * colors nodes by quiz results anymore). Used by the teacher's
- * graph-as-context selection (graph-context.ts) to find diagnostic
- * hotspots; the home renderer does not consume it. Nodes with no quiz
- * events have no entry. (The graph-as-context consumer is shelved —
- * docs/probe-teach-split.md §5 — but the event fact stays.)
+ * colors nodes by quiz results anymore). Its last consumer, the
+ * graph-as-context selection, died in wave 7 (the injection is gone —
+ * the prober reads its map through tools now); the event fact stays as
+ * raw ledger truth. Nodes with no quiz events have no entry.
  */
 export function latestQuizOutcomes(nodes: GraphNode[], events: LedgerEvent[]): Map<string, LedgerEventKind> {
 	const latest = new Map<string, { at: string; kind: LedgerEventKind; index: number }>();