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/settings.test.ts

@@ -53,7 +53,7 @@ describe("sanitizeUserSettings", () => {
 		const record = {
 			version: 1,
 			general: { autoUpdate: false },
-			chat: { model: { provider: "openrouter", id: "z-ai/glm-5.3-flash" }, thinkingLevel: "low", graphContextTokens: 256 },
+			chat: { model: { provider: "openrouter", id: "z-ai/glm-5.3-flash" }, thinkingLevel: "low" },
 			agent: {
 				models: {
 					researcher: { model: { provider: "openrouter", id: "qwen/qwen3.8-flash" }, thinkingLevel: "high" },