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.

2 files changed, 17 insertions, 0 deletions

diff --git a/src/core/wire/conformance.test.ts b/src/core/wire/conformance.test.ts
index f5d6608..58cba3a 100644
--- a/src/core/wire/conformance.test.ts
+++ b/src/core/wire/conformance.test.ts
@@ -140,6 +140,17 @@ describe("classifies every WsServerMessage type", () => {
 			},
 			{ type: "chat.error" as const, message: "e" },
 			{ type: "conversation.open" as const, conversationId: "c1" },
+			{
+				type: "conversation.statusChanged" as const,
+				conversationId: "c1",
+				status: "active" as const,
+			},
+			{
+				type: "conversation.compacted" as const,
+				conversationId: "c1",
+				messagesSummarized: 10,
+				messagesKept: 5,
+			},
 		];
 		const labels = msgs.map(assertWsServerMessageExhaustive);
 		expect(labels).toEqual([
@@ -150,6 +161,8 @@ describe("classifies every WsServerMessage type", () => {
 			"chat.delta",
 			"chat.error",
 			"conversation.open",
+			"conversation.statusChanged",
+			"conversation.compacted",
 		]);
 	});
 });
diff --git a/src/core/wire/conformance.ts b/src/core/wire/conformance.ts
index 05a15aa..07808fc 100644
--- a/src/core/wire/conformance.ts
+++ b/src/core/wire/conformance.ts
@@ -83,6 +83,10 @@ export function assertWsServerMessageExhaustive(msg: WsServerMessage): string {
 			return "chat.error";
 		case "conversation.open":
 			return "conversation.open";
+		case "conversation.statusChanged":
+			return "conversation.statusChanged";
+		case "conversation.compacted":
+			return "conversation.compacted";
 		default:
 			return msg satisfies never;
 	}