v1 web interface: dispatch-mode quiz/ask, Fastify+WS server, React frontend, deterministic test suite

- extensions/core/question-core.ts: pure quiz/ask logic (normalize/shuffle/resolve/grade/format) shared by both interfaces
- extensions/core/bridge.ts: in-process server<->extension bridge (answer/dismiss/re-arm)
- extensions/quiz-web.ts + ask-web.ts: web dispatch mode — tool returns immediately, graded answer arrives as next user message; sessions resumable mid-question via lh_question/lh_question_answered custom entries (never in LLM context)
- extensions/quiz.ts: refactored onto shared core (terminal blocking mode unchanged)
- src/server/index.ts: Fastify + WebSocket; REST (list/create/resume), entry sync (diff-based, all message kinds), streaming deltas, pending-question push
- web/: Vite + React — home view (graph placeholder, session list, new-session input), session view (markdown+KaTeX+mermaid transcript, quiz cards, streaming)
- src/testing/scripted-model.ts: deterministic fake LLM (scripted model runtime injected via factory overrides)
- tests/: 48 deterministic tests (unit: question-core + bridge; integration: full pi loop with scripted model incl. resume re-arm)
- scripts/e2e.ts: live smoke test (manual, real LLM, never a gate)
- teacher/system-prompt.md: end-your-turn rule for question tools

src/shared/protocol.ts

@@ -0,0 +1,64 @@
+/**
+ * protocol — shared types between the web server and the browser client.
+ * One source of truth for the WS protocol and REST DTOs.
+ */
+
+import type { ClientQuestion, QuestionAnswerData } from "../../extensions/core/question-core.ts";
+
+export type { ClientQuestion, QuestionAnswerData } from "../../extensions/core/question-core.ts";
+
+// ─── entries (session → client) ─────────────────────────────────────────────
+
+export interface ClientToolCall {
+	name: string;
+	args: Record<string, unknown>;
+}
+
+export type ClientEntry =
+	| { type: "user"; id: string; text: string }
+	| { type: "assistant"; id: string; text: string; toolCalls: ClientToolCall[] }
+	| { type: "toolResult"; id: string; toolName: string; text: string }
+	| { type: "question"; id: string; data: ClientQuestion }
+	| { type: "questionAnswered"; id: string; data: QuestionAnswerData }
+	| { type: "meta"; id: string; kind: string };
+
+// ─── REST DTOs ──────────────────────────────────────────────────────────────
+
+export interface SessionSummary {
+	id: string;
+	file: string;
+	name?: string;
+	createdAt: string;
+	updatedAt: string;
+	messageCount: number;
+	preview?: string;
+}
+
+export interface NewSessionResponse {
+	id: string;
+}
+
+// ─── WS protocol ────────────────────────────────────────────────────────────
+
+export type ServerMessage =
+	| { type: "hello"; sessionId: string | null }
+	| { type: "backfill"; entries: ClientEntry[] }
+	| { type: "entry"; entry: ClientEntry }
+	| { type: "pending"; question: ClientQuestion | null }
+	| { type: "delta"; delta: string }
+	| { type: "streaming"; value: boolean }
+	| { type: "error"; message: string };
+
+export type ClientMessage =
+	| { type: "prompt"; text: string }
+	| {
+			type: "answer";
+			questionId: string;
+			dontKnow?: boolean;
+			values?: string[];
+			other?: string;
+			text?: string;
+			note?: string;
+	  }
+	| { type: "dismiss"; questionId: string }
+	| { type: "abort" };