feat: graph context injection — the session's prior knowledge, steered in at session start (vision-context-injection.md)

One shot per chat, fired at the first turn's onFinish: the session's
topic (its only typed message) is embedded as an EmbeddingGemma retrieval
query; the semantically closest graph propositions are selected under the
session's token budget (pure budget, no similarity threshold — the
decided doctrine) and delivered as a marker-only steer through the wake
pipeline, queuing behind pending questions like every sub-agent result.

- contracts: ChatSettings.graphContextTokens (default 1024, max 4096,
  step 128, 0 = off); GraphContextData + graphContextText; the
  graph-context JobKind + buildGraphContextSteer (id steer_ctx_<chatId>)
- core/graph-context.ts: brute-force cosine top-K, greedy chars/4 fill
  under budget, most-recent UnderstandingLevel fold, count cap 64,
  parse-don't-cast at the marker seam
- server: embedQuery (role-asymmetric query format, same warm singleton
  — vector-space parity by construction); the runner (startGraphContext-
  Injection one-shot gates; runGraphContextJob validates ledger parity);
  wake branches (chatIdOf/jobIdOf, finalizeJob done, recoverStaleJobs
  re-deliver or contextRespawn); abortJob kills context jobs SILENTLY
  (nothing was promised in the lesson); turn-service trigger seam
- adapter: data-graph-context flattens to the canonical block (malformed
  parts have no model face)
- UI: the budget slider (home dock + /chat/new draft, the session-data
  strip); the quiet SystemLine "~537 · 10 propositions"; dock kind
  "Knowledge context"; model-picker PUT now spreads settings (a model
  pick can no longer clear the sibling override)

Live-smoked end to end on the real embedder + real GLM: seeded ledger
(10 propositions), session on "modal logic: possible worlds and the
necessity box" — job in the dock, queued behind the prober's question,
delivered on the answer, SystemLine in the transcript, wake turn reads
the block and continues the probe. Gates: tsc, lint, 459/459, build.

src/core/contracts/jobs.ts

@@ -7,11 +7,11 @@
  * of "ai" (safe everywhere: server, client, tests). See docs/vision.md.
  */
 import type { UIMessage } from "ai";
-import type { CallUsage } from "./chat.ts";
+import type { CallUsage, GraphContextData } from "./chat.ts";
 
 // ─── Async sub-agent jobs (vision §2.5; plan.md Wave 0 protocol) ────────────
 
-export type JobKind = "research" | "demo" | "visual";
+export type JobKind = "research" | "demo" | "visual" | "graph-context";
 export type JobStatus = "running" | "done" | "error";
 
 export interface JobRecord {
@@ -263,7 +263,11 @@ export interface AbortSteerMessage extends UIMessage {
 }
 
 /** Anything the wake pipeline may queue and deliver. */
-export type SteerMessage = SubagentSteerMessage | AbortSteerMessage | ProbeHandoffSteerMessage;
+export type SteerMessage =
+	| SubagentSteerMessage
+	| AbortSteerMessage
+	| ProbeHandoffSteerMessage
+	| GraphContextSteerMessage;
 
 /** Whether a result is the failure shape (html/svg empty, failure brief). */
 export function isSubagentFailure(kind: JobKind, result: ResearchResult | DemoResult | VisualResult): boolean {
@@ -380,6 +384,34 @@ export function buildProbeHandoffSteer(chatId: string): ProbeHandoffSteerMessage
 	};
 }
 
+// ─── the graph-context steer (vision-context-injection.md) ───────────────────
+//
+// The injection's delivery: same wake pipeline, same gates — it queues
+// behind a pending quiz and rides the turn after the learner's answer, or
+// fires in the pump's idle window. Marker-only (the custom-message scheme):
+// no text part; the adapter flattens data-graph-context to graphContextText
+// (core/contracts/chat.ts owns the wording). One per chat, ever — the id is
+// deterministic per chat, so re-delivery is idempotent.
+
+export interface GraphContextSteerMessage extends UIMessage {
+	id: `steer_ctx_${string}`;
+	role: "user";
+	metadata: { graphContext: { chatId: string; jobId: string } };
+	parts: [{ type: "data-graph-context"; data: GraphContextData }];
+}
+
+export function buildGraphContextSteer(
+	meta: { chatId: string; jobId: string },
+	data: GraphContextData,
+): GraphContextSteerMessage {
+	return {
+		id: `steer_ctx_${meta.chatId}`,
+		role: "user",
+		metadata: { graphContext: meta },
+		parts: [{ type: "data-graph-context", data }],
+	};
+}
+
 /** True when the transcript already carries this steer — idempotent
  *  delivery for ANY steer kind: every steer id is deterministic per its
  *  event (steer_<jobId> for jobs, steer_probe_<chatId> for the handoff). */