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.

components/new-session.tsx

@@ -5,7 +5,6 @@ import { useRouter } from "next/navigation";
 import { Conversation, ConversationContent, ConversationEmptyState } from "@/components/ai-elements/conversation";
 import { Composer } from "@/components/composer";
 import { DictationBar, useDictation } from "@/components/dictation";
-import { GraphContextControl, effectiveContextTokens } from "@/components/graph-context-control";
 import { useDefaultSettings } from "@/components/default-settings";
 import { PhaseChip } from "@/components/phase-divider";
 import { SidebarToggle } from "@/components/sidebar";
@@ -131,17 +130,6 @@ export function DraftShell({
 								<StatsBar
 									dictationSlot={<DictationBar dictation={dictation} />}
 									turns={[]}
-									// The session-data slot (owner, 2026-09-15): pre-chat the left
-									// side is free — the knowledge-context budget lives exactly
-									// where session data will sit once a session exists.
-									leftSlot={
-										<GraphContextControl
-											value={effectiveContextTokens(settings)}
-											onChange={(tokens) =>
-												onSettingsSaved({ ...settings, graphContextTokens: tokens })
-											}
-										/>
-									}
 								/>
 							</div>
 						</div>