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

2 files changed, 2 insertions, 0 deletions

diff --git a/packages/kernel/src/contracts/conversation.ts b/packages/kernel/src/contracts/conversation.ts
index f1f8d77..9b7d2f6 100644
--- a/packages/kernel/src/contracts/conversation.ts
+++ b/packages/kernel/src/contracts/conversation.ts
@@ -9,6 +9,7 @@ export type {
 	ChatMessage,
 	Chunk,
 	ConversationMeta,
+	ConversationStatus,
 	ErrorChunk,
 	Role,
 	StepId,
diff --git a/packages/kernel/src/contracts/index.ts b/packages/kernel/src/contracts/index.ts
index d39853e..3aa9740 100644
--- a/packages/kernel/src/contracts/index.ts
+++ b/packages/kernel/src/contracts/index.ts
@@ -16,6 +16,7 @@ export type {
 	ChatMessage,
 	Chunk,
 	ConversationMeta,
+	ConversationStatus,
 	ErrorChunk,
 	Role,
 	StepId,