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.

tests/merge-adopted.test.ts

@@ -13,7 +13,10 @@ function userText(id: string, text: string): TeacherUIMessage {
 	return { id, role: "user", parts: [{ type: "text", text }] };
 }
 function steer(id: string): TeacherUIMessage {
-	return { id, role: "user", parts: [{ type: "data-graph-context", data: { chatId: "c", budget: 1024, tokens: 1, propositions: [] } }] };
+	// Wave 7 killed the graph-context injection; its marker part is gone.
+	// The steer-shaped user message here exercises mergeAdopted's
+	// non-text user parts path with the handoff marker instead.
+	return { id, role: "user", parts: [{ type: "data-probe-handoff", data: { chatId: "c" } }] };
 }
 function assistant(id: string): TeacherUIMessage {
 	return { id, role: "assistant", parts: [{ type: "text", text: "reply" }] };