feat(tabs): cross-device tab sync via conversation lifecycle

Consume the conversation lifecycle handoff ([email protected], [email protected]).
Re-pinned file: deps + re-mirrored .dispatch/*.reference.md.

- fetchOpenConversations() on connect: GET /conversations?status=active,idle
  restores the tab bar across devices (merges with localStorage — opens new
  tabs, removes closed ones, updates titles from backend)
- conversation.statusChanged WS handler: closed → removeTabLocally (no
  re-POST); active → open tab + spinner; idle → update status map
- conversation.compacted WS handler: dispose stale store + cache, reload
  history from server
- TabBar shows a spinner on active conversations (statusFor prop)
- closeTab refactored to use removeTabLocally (extracted cleanup)
- conformance guards + WS adapter tests cover all 3 new WsServerMessage types

686 tests green.

4 files changed, 98 insertions, 0 deletions

diff --git a/src/adapters/ws/index.test.ts b/src/adapters/ws/index.test.ts
index e13f123..92d57a8 100644
--- a/src/adapters/ws/index.test.ts
+++ b/src/adapters/ws/index.test.ts
@@ -293,6 +293,34 @@ describe("createSurfaceSocket", () => {
 		expect(onChat).not.toHaveBeenCalled();
 	});
 
+	it("routes conversation.statusChanged to onConversationStatusChanged", () => {
+		const ws = fakeSocket();
+		const onMessage = vi.fn();
+		const onConversationStatusChanged = vi.fn();
+		createSurfaceSocket({
+			url: "ws://test",
+			onMessage,
+			onConversationStatusChanged,
+			socketFactory: () => ws,
+		});
+
+		ws.resolveOpen();
+		ws.invokeMessage(
+			JSON.stringify({
+				type: "conversation.statusChanged",
+				conversationId: "c1",
+				status: "active",
+			}),
+		);
+		expect(onConversationStatusChanged).toHaveBeenCalledOnce();
+		expect(onConversationStatusChanged).toHaveBeenCalledWith({
+			type: "conversation.statusChanged",
+			conversationId: "c1",
+			status: "active",
+		});
+		expect(onMessage).not.toHaveBeenCalled();
+	});
+
 	it("still routes surface catalog/surface to onMessage", () => {
 		const ws = fakeSocket();
 		const onMessage = vi.fn();
diff --git a/src/adapters/ws/index.ts b/src/adapters/ws/index.ts
index 18ebdf7..d2bc13d 100644
--- a/src/adapters/ws/index.ts
+++ b/src/adapters/ws/index.ts
@@ -1,7 +1,9 @@
 import type {
 	ChatDeltaMessage,
 	ChatErrorMessage,
+	ConversationCompactedMessage,
 	ConversationOpenMessage,
+	ConversationStatusChangedMessage,
 	WsClientMessage,
 } from "@dispatch/transport-contract";
 import type { SurfaceServerMessage } from "@dispatch/ui-contract";
@@ -21,6 +23,10 @@ export interface SurfaceSocketOptions {
 	onChat?: (msg: ChatDeltaMessage | ChatErrorMessage) => void;
 	/** Broadcast when a conversation is "opened" (e.g. CLI `--open` flag). */
 	onConversationOpen?: (msg: ConversationOpenMessage) => void;
+	/** Broadcast when a conversation's lifecycle status changes (active/idle/closed). */
+	onConversationStatusChanged?: (msg: ConversationStatusChangedMessage) => void;
+	/** Broadcast when a conversation's history has been compacted (reload needed). */
+	onConversationCompacted?: (msg: ConversationCompactedMessage) => void;
 	onReopen?: () => void;
 	socketFactory?: (url: string) => WebSocketLike;
 }
@@ -65,6 +71,10 @@ export function createSurfaceSocket(opts: SurfaceSocketOptions): SurfaceSocketHa
 					opts.onChat?.(msg as ChatDeltaMessage | ChatErrorMessage);
 				} else if (msg.type === "conversation.open") {
 					opts.onConversationOpen?.(msg as ConversationOpenMessage);
+				} else if (msg.type === "conversation.statusChanged") {
+					opts.onConversationStatusChanged?.(msg as ConversationStatusChangedMessage);
+				} else if (msg.type === "conversation.compacted") {
+					opts.onConversationCompacted?.(msg as ConversationCompactedMessage);
 				} else {
 					opts.onMessage(msg as SurfaceServerMessage);
 				}
diff --git a/src/adapters/ws/logic.test.ts b/src/adapters/ws/logic.test.ts
index ca129c0..2463519 100644
--- a/src/adapters/ws/logic.test.ts
+++ b/src/adapters/ws/logic.test.ts
@@ -233,6 +233,37 @@ describe("parseServerMessage", () => {
 			parseServerMessage(JSON.stringify({ type: "conversation.open", conversationId: 42 })),
 		).toBeNull();
 	});
+
+	it("parses a conversation.statusChanged message", () => {
+		const data = JSON.stringify({
+			type: "conversation.statusChanged",
+			conversationId: "c1",
+			status: "active",
+		});
+		expect(parseServerMessage(data)).toEqual({
+			type: "conversation.statusChanged",
+			conversationId: "c1",
+			status: "active",
+		});
+	});
+
+	it("returns null for conversation.statusChanged with invalid status", () => {
+		expect(
+			parseServerMessage(
+				JSON.stringify({
+					type: "conversation.statusChanged",
+					conversationId: "c1",
+					status: "done",
+				}),
+			),
+		).toBeNull();
+	});
+
+	it("returns null for conversation.statusChanged with missing conversationId", () => {
+		expect(
+			parseServerMessage(JSON.stringify({ type: "conversation.statusChanged", status: "idle" })),
+		).toBeNull();
+	});
 });
 
 describe("round-trip: parseServerMessage(serialize(...))", () => {
diff --git a/src/adapters/ws/logic.ts b/src/adapters/ws/logic.ts
index a9b70ff..53955f8 100644
--- a/src/adapters/ws/logic.ts
+++ b/src/adapters/ws/logic.ts
@@ -1,7 +1,9 @@
 import type {
 	ChatDeltaMessage,
 	ChatErrorMessage,
+	ConversationCompactedMessage,
 	ConversationOpenMessage,
+	ConversationStatusChangedMessage,
 	WsClientMessage,
 	WsServerMessage,
 } from "@dispatch/transport-contract";
@@ -20,6 +22,8 @@ const VALID_SERVER_TYPES = new Set([
 	"chat.delta",
 	"chat.error",
 	"conversation.open",
+	"conversation.statusChanged",
+	"conversation.compacted",
 ]);
 
 /** Serialize a client message to a JSON string for the wire. */
@@ -117,6 +121,31 @@ export function parseServerMessage(data: string): WsServerMessage | null {
 			};
 			return msg;
 		}
+		case "conversation.statusChanged": {
+			if (typeof parsed.conversationId !== "string") return null;
+			if (typeof parsed.status !== "string") return null;
+			if (parsed.status !== "active" && parsed.status !== "idle" && parsed.status !== "closed") {
+				return null;
+			}
+			const msg: ConversationStatusChangedMessage = {
+				type: "conversation.statusChanged",
+				conversationId: parsed.conversationId,
+				status: parsed.status,
+			};
+			return msg;
+		}
+		case "conversation.compacted": {
+			if (typeof parsed.conversationId !== "string") return null;
+			if (typeof parsed.messagesSummarized !== "number") return null;
+			if (typeof parsed.messagesKept !== "number") return null;
+			const msg: ConversationCompactedMessage = {
+				type: "conversation.compacted",
+				conversationId: parsed.conversationId,
+				messagesSummarized: parsed.messagesSummarized,
+				messagesKept: parsed.messagesKept,
+			};
+			return msg;
+		}
 		default:
 			return null;
 	}