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/server/chat-handler.ts

@@ -4,14 +4,15 @@ import { createProberAgent, createTeacherAgent, type TeachingAgent } from "../ag
 import { piEngineFor } from "../agent/models.ts";
 import { createJobRunner } from "../agent/subagents/runner.ts";
 import { createExtractionPipeline } from "../agent/subagents/extraction.ts";
-import { embedNewNodes } from "./embeddings.ts";
+import { runGraphContextJob, type GraphContextDeps } from "../agent/subagents/graph-context.ts";
+import { EMBEDDING_DIM, EMBEDDING_MODEL, embedNewNodes, embedQuery } from "./embeddings.ts";
 import type { ModelRole } from "../../config.ts";
-import { claimSteers, deliverJobResult, setJobRespawn, setTurnRunner } from "./jobs.ts";
+import { claimSteers, deliverJobResult, setContextRespawn, setJobRespawn, setTurnRunner } from "./jobs.ts";
 import { recordToPiMessages } from "./pi/record-adapter.ts";
 import { createPiTurnResponse } from "./pi/ui-stream.ts";
 import { stores } from "./stores.ts";
 import { beginTurn, endTurn } from "./turn-liveness.ts";
-import { persistTurn, triggerExtraction, withMessageIds } from "./turn-service.ts";
+import { persistTurn, triggerExtraction, triggerGraphContext, withMessageIds } from "./turn-service.ts";
 import type { CallUsage } from "../core/contracts.ts";
 
 /**
@@ -48,6 +49,18 @@ export const extraction = createExtractionPipeline({
 	embedder: embedNewNodes,
 });
 
+/** Graph context injection (vision-context-injection.md): the runner's
+ *  deps — same storage ports, the REAL embedder as the query seam (same
+ *  warm singleton as extraction, so vector-space parity holds by
+ *  construction), and the wake pipeline as the delivery seam. */
+export const graphContext: GraphContextDeps = {
+	chatStore: stores.chatStore,
+	jobStore: stores.jobStore,
+	graphStore: stores.graphStore,
+	embedder: { model: EMBEDDING_MODEL, dim: EMBEDDING_DIM, embedQuery },
+	deliver: deliverJobResult,
+};
+
 // Wake-pipeline wiring (contracts.ts "THE ASYNC PROTOCOL" §4): the pipeline
 // fires its server-side teacher turns through THIS composition root, and
 // crash recovery re-spawns orphaned sub-agent loops through THIS runner.
@@ -65,6 +78,7 @@ setTurnRunner(async (chatId, messages) => {
 	return res.status;
 });
 setJobRespawn((jobId) => void jobRunner.runJob(jobId));
+setContextRespawn((jobId) => void runGraphContextJob(graphContext, jobId));
 
 /** The message-shape gate the SDK's UIMessageValidator owned: a malformed
  *  body must fail BEFORE the stream exists — the path where no onFinish will
@@ -223,6 +237,9 @@ export async function handleChatRequest(
 					});
 				}
 				triggerExtraction(stores, extraction, chatId);
+				// The graph READ channel: one-shot prior-knowledge injection at
+				// session start — a no-op for every session past its start.
+				triggerGraphContext(graphContext, chatId);
 				// LAST: a poller that sees not-in-flight must read an already-persisted
 				// record — endTurn only after persistTurn has done its job.
 				endTurn(chatId);