feat: conversation lifecycle status (active/idle/closed) for tab persistence

Implement roadmap item 9: tab persistence across devices.

Wire (0.10.0):
- Add ConversationStatus type (active | idle | closed)
- Add status field to ConversationMeta

Transport-contract (0.14.0):
- Add conversation.statusChanged WS message to WsServerMessage union
- Re-export ConversationStatus

Conversation-store:
- Track status in ConversationMetaRow (default: idle)
- getConversationStatus / setConversationStatus methods
- listConversations accepts { status: ConversationStatus[] } filter
- Old meta rows without status default to idle on read

Session-orchestrator:
- conversationStatusChanged hook descriptor
- Emit on transitions: idle→active (turn start), active→idle (turn settle),
  →closed (closeConversation)
- Persist status to store as fire-and-forget side effect
- Declare hook in manifest contributes.hooks

Transport-ws:
- Subscribe to conversationStatusChanged hook
- Broadcast conversation.statusChanged WS message to all clients

Transport-http:
- GET /conversations?status=active,idle filter (parseStatusFilter pure helper)
- POST /conversations/:id/close now sets status to closed

CLI:
- dispatch list defaults to active,idle (excludes closed)
- --status <state> flag to filter by single status
- --all flag to include closed

FE handoff: frontend-conversation-lifecycle-handoff.md

1 files changed, 15 insertions, 1 deletions

diff --git a/packages/transport-contract/src/index.ts b/packages/transport-contract/src/index.ts
index d8bfe50..237f4ab 100644
--- a/packages/transport-contract/src/index.ts
+++ b/packages/transport-contract/src/index.ts
@@ -23,6 +23,7 @@ import type { SurfaceClientMessage, SurfaceServerMessage } from "@dispatch/ui-co
 import type {
 	AgentEvent,
 	ConversationMeta,
+	ConversationStatus,
 	QueuedMessage,
 	ReasoningEffort,
 	StoredChunk,
@@ -32,6 +33,7 @@ import type {
 export type {
 	AgentEvent,
 	ConversationMeta,
+	ConversationStatus,
 	QueuedMessage,
 	ReasoningEffort,
 	StepMetrics,
@@ -483,7 +485,8 @@ export type WsServerMessage =
 	| SurfaceServerMessage
 	| ChatDeltaMessage
 	| ChatErrorMessage
-	| ConversationOpenMessage;
+	| ConversationOpenMessage
+	| ConversationStatusChangedMessage;
 
 // ─── Conversation list + metadata ────────────────────────────────────────────
 
@@ -498,6 +501,17 @@ export interface ConversationOpenMessage {
 }
 
 /**
+ * Broadcast to all connected WS clients when a conversation's lifecycle status
+ * changes (active/idle/closed). The frontend uses this to sync tab state across
+ * devices in real time.
+ */
+export interface ConversationStatusChangedMessage {
+	readonly type: "conversation.statusChanged";
+	readonly conversationId: string;
+	readonly status: ConversationStatus;
+}
+
+/**
  * Response for `GET /conversations` — the list of all known conversations,
  * sorted by `lastActivityAt` descending (most recent first). Each entry carries
  * enough metadata for a conversation picker UI (id, title, timestamps).