extraction cleanup: events ledger dies, markdown source view, auditor-as-linker (2026-09-27 rulings)

The graph becomes raw reasoning chains only. Quiz outcomes and
understanding observations are no longer formalized; assessment
moves to the future practice module.

Events ledger removed end-to-end: LedgerEvent/LedgerEventKind/
UnderstandingLevel/ExtractionAttribution/AuditResult.dropped and
snapshot nodeObservations deleted from contracts; quizEvent builder
and the events step of mergeFindings gone; appendEvent/readEvents
dropped from the port and store; LEDGER_FILES loses events.jsonl
with a one-time purge of a stale file next to the nodes ledger;
graph-deletion and the delete dialog lose event purge + quiz-answer
impact counts; GraphSessionProposition becomes a pure birth list.

Whole-session markdown source view: new core/session-markdown.ts is
the shared formatting engine (id-anchored speaker blocks, quiz/
recall/question blocks, tool one-liners) — the extractor's prompt
view and the future user-facing export render from one engine.
Coverage fingerprints deliberately stay on the old line format
(content-hash semantics; re-formatting never re-opens covered
history). The whole session goes to the extractor — no phase cut.

Auditor refocused as the identity linker: never sees the source;
explores the graph via new auditor-specific tools in
agent/tools/graph.ts (find — glob over name/statement/aliases;
list_sessions; list_propositions with full statement text; no
timestamps) instead of an injected full-graph dump; equivalence
bias — paraphrases merge, only genuinely distinct propositions stay
apart; no drop channel, the extractor is fully trusted; may draw
bridging edges (typed follows/supports) between existing nodes and
the batch, resolved by the merger with chat-scoped message-less
provenance. Agentic loop, maxTurns 16.

UI: the node detail card gains an edges section above the sessions
list (follows-from / supported-by / what-follows / what-it-supports,
rendered only when present, click-to-select neighbors); the
understanding-note chips are gone.

Prober list_propositions reworded to what a session covered —
names only, no levels. docs/architecture.md + README updated to
the as-built pipeline. Gates: typecheck, 1059/1059, lint, build.

tests/session-markdown.test.ts

@@ -0,0 +1,138 @@
+/**
+ * The shared session-markdown engine (core/session-markdown.ts, owner ruling
+ * 2026-09-27): ONE renderer for the extractor's source view and the future
+ * user-facing session export — id-anchored speaker blocks, readable
+ * quiz/recall/question blocks, one-line notes for other tools. Pinned here:
+ * block shapes, anchor handling (on/off), title header, empty-message
+ * skipping, and content parity with the coverage line builder.
+ */
+
+import assert from "node:assert/strict";
+import { describe, it } from "node:test";
+import type { LhMessage } from "../src/core/native-messages.ts";
+import { messageMarkdown, sessionMarkdown } from "../src/core/session-markdown.ts";
+import { messageViewLines } from "../src/core/coverage.ts";
+import { coverageSlots } from "../src/core/coverage.ts";
+
+function user(id: string, text: string): LhMessage {
+	return { id, role: "user", content: text, timestamp: Date.now() } as never;
+}
+
+function teacher(id: string, text: string): LhMessage {
+	return {
+		id,
+		role: "assistant",
+		content: [{ type: "text", text }],
+		api: "openai-completions",
+		provider: "openrouter",
+		model: "test",
+		usage: { input: 0, output: 0, cacheRead: 0, cacheWrite: 0 },
+		stopReason: "stop",
+		timestamp: Date.now(),
+	} as never;
+}
+
+function result(
+	id: string,
+	toolCallId: string,
+	toolName: string,
+	details: unknown,
+	isError = false,
+): LhMessage {
+	return {
+		id,
+		role: "toolResult",
+		toolCallId,
+		toolName,
+		content: [{ type: "text", text: "ok" }],
+		details,
+		isError,
+		timestamp: Date.now(),
+	} as never;
+}
+
+describe("messageMarkdown", () => {
+	it("renders speaker blocks with the id anchor", () => {
+		const md = messageMarkdown(user("u1", "teach me the chain rule"), "u1");
+		assert.equal(md, "### Learner · u1\n\nteach me the chain rule");
+		const md2 = messageMarkdown(teacher("a1", "The derivative measures change."), "a1");
+		assert.equal(md2, "### Teacher · a1\n\nThe derivative measures change.");
+	});
+
+	it("anchors off — the same document without the ids (the user export)", () => {
+		const md = messageMarkdown(user("u1", "hello"), "u1", false);
+		assert.equal(md, "### Learner\n\nhello");
+	});
+
+	it("quiz blocks: question + outcome + the learner's note", () => {
+		const md = messageMarkdown(
+			result("r1", "q1", "quiz", { questionText: "What is a derivative?", correct: false, dontKnow: false, note: "mixed up signs" }),
+			"r1",
+		)!;
+		assert.match(md, /^### Quiz · r1$/m);
+		assert.match(md, /\*\*Q:\*\* What is a derivative\?/);
+		assert.match(md, /The learner answered incorrectly\./);
+		assert.match(md, /\*\(his thinking: mixed up signs\)\*/);
+	});
+
+	it("explain results: the learner's own words are shown", () => {
+		const md = messageMarkdown(
+			result("r1", "e1", "explain", { questionText: "Why does Mercury stay near the Sun?", text: "it never strays far" }),
+			"r1",
+		)!;
+		assert.match(md, /^### Recall check · r1$/m);
+		assert.match(md, /The learner answered in his own words: it never strays far/);
+	});
+
+	it("ask blocks: question + chosen options + free text", () => {
+		const chosen = messageMarkdown(
+			result("r1", "a1", "ask_user_question", { questionText: "Which way?", answers: ["second"], other: "also the third" }),
+			"r1",
+		)!;
+		assert.match(chosen, /^### Question · r1$/m);
+		assert.match(chosen, /The learner chose: second, also the third/);
+		const free = messageMarkdown(
+			result("r2", "a2", "ask_user_question", { questionText: "Why?", text: "because" }),
+			"r2",
+		)!;
+		assert.match(free, /The learner answered: because/);
+	});
+
+	it("other clean tool results: one line; failed calls and markers: nothing", () => {
+		assert.equal(messageMarkdown(result("r1", "j1", "research", { brief: "long" }), "r1"), "### Tool · r1\n\n*research result delivered*");
+		assert.equal(messageMarkdown(result("r2", "j2", "research", {}, true), "r2"), null, "a failed call is retry context");
+		assert.equal(messageMarkdown(user("u3", "   "), "u3"), null, "empty text renders nothing");
+	});
+});
+
+describe("sessionMarkdown", () => {
+	it("assembles blocks in order under the title header, skipping nothings", () => {
+		const md = sessionMarkdown([user("u1", "go"), teacher("a1", "First."), user("u2", "  ")], { title: "My session" });
+		assert.equal(md, "# My session\n\n### Learner · u1\n\ngo\n\n### Teacher · a1\n\nFirst.");
+	});
+
+	it("no title → no header; anchors default on", () => {
+		const md = sessionMarkdown([user("u1", "go")]);
+		assert.equal(md, "### Learner · u1\n\ngo");
+	});
+
+	it("content parity with the coverage line builder (2026-09-27 split)", () => {
+		// Every message that produces view lines produces a markdown block,
+		// and every message that renders nothing renders nothing in either —
+		// same messages, two formats, one seam decision. The FINGERPRINT
+		// stays on the line format (stable — no mass re-extraction when
+		// presentation changes); markdown is presentation only.
+		const messages: LhMessage[] = [
+			user("u1", "teach me"),
+			teacher("a1", "The chain rule multiplies local rates."),
+			result("r1", "q1", "quiz", { questionText: "Q?", correct: true, dontKnow: false }),
+			result("r2", "j1", "research", { brief: "b" }),
+			result("r3", "j2", "research", {}, true),
+		];
+		for (const message of messages) {
+			const hasLines = messageViewLines(message, message.id).length > 0;
+			const hasMarkdown = messageMarkdown(message, message.id) !== null;
+			assert.equal(hasMarkdown, hasLines, `parity for ${message.id}`);
+		}
+	});
+});