fix: conversation.open opens tab without auto-switching

CLI --open should add the tab to the strip but leave the user on their
current tab. Add openTab reducer (add without selecting) + use it in
openConversation instead of createTab+selectTab.

3 files changed, 32 insertions, 21 deletions

diff --git a/src/app/store.svelte.ts b/src/app/store.svelte.ts
index 5159353..5a5245d 100644
--- a/src/app/store.svelte.ts
+++ b/src/app/store.svelte.ts
@@ -434,29 +434,23 @@ export function createAppStore(opts?: CreateAppStoreOptions): AppStore {
 	let socket: ReturnType<typeof createSurfaceSocket> | null = null;
 
 	/**
-	 * Open (or focus) a conversation tab — used by the `conversation.open` WS
-	 * broadcast (CLI `--open` flag). If the conversation is already open, just
-	 * focus it; otherwise create a chat store, load its history, subscribe to its
-	 * live turns, and create+select the tab.
+	 * Open a conversation tab — used by the `conversation.open` WS broadcast
+	 * (CLI `--open` flag). If the conversation is already open, this is a no-op;
+	 * otherwise create a chat store, load its history, subscribe to its live
+	 * turns, and add the tab WITHOUT switching the active conversation (the user
+	 * stays on their current tab; the new tab appears in the strip).
 	 */
 	function openConversation(conversationId: string): void {
-		const alreadyOpen = chatStores.has(conversationId);
-		if (!alreadyOpen) {
-			const store = createChatFor(conversationId, activeModel);
-			chatStores.set(conversationId, store);
-			void store.load();
-			subscribeChat(conversationId);
-			tabsStore.createTab({
-				conversationId,
-				model: activeModel,
-				title: "Conversation",
-			});
-		}
-		tabsStore.selectTab(conversationId);
-		refreshActiveChat();
-		syncSubscriptions();
-		void refreshCwd();
-		void refreshReasoningEffort();
+		if (chatStores.has(conversationId)) return;
+		const store = createChatFor(conversationId, activeModel);
+		chatStores.set(conversationId, store);
+		void store.load();
+		subscribeChat(conversationId);
+		tabsStore.openTab({
+			conversationId,
+			model: activeModel,
+			title: "Conversation",
+		});
 	}
 
 	const socketOpts: SurfaceSocketOptions = {
diff --git a/src/features/tabs/tabs-store.svelte.ts b/src/features/tabs/tabs-store.svelte.ts
index cba527e..2e876f9 100644
--- a/src/features/tabs/tabs-store.svelte.ts
+++ b/src/features/tabs/tabs-store.svelte.ts
@@ -4,6 +4,7 @@ import {
 	closeTab as reduceCloseTab,
 	createTab as reduceCreateTab,
 	newDraft as reduceNewDraft,
+	openTab as reduceOpenTab,
 	selectTab as reduceSelectTab,
 	setModel as reduceSetModel,
 	setTitle as reduceSetTitle,
@@ -21,6 +22,8 @@ export interface TabsStore {
 	readonly activeTab: Tab | null;
 	newDraft(): void;
 	createTab(tab: Tab): void;
+	/** Add a tab WITHOUT focusing it (for `conversation.open`). No-op if already open. */
+	openTab(tab: Tab): void;
 	selectTab(conversationId: string): void;
 	closeTab(conversationId: string): void;
 	setModel(conversationId: string, model: string): void;
@@ -51,6 +54,9 @@ export function createTabsStore(storage: TabsStorage): TabsStore {
 		createTab(tab: Tab): void {
 			apply(reduceCreateTab(state, tab));
 		},
+		openTab(tab: Tab): void {
+			apply(reduceOpenTab(state, tab));
+		},
 		selectTab(conversationId: string): void {
 			apply(reduceSelectTab(state, conversationId));
 		},
diff --git a/src/features/tabs/tabs.ts b/src/features/tabs/tabs.ts
index 61ae58e..3360d3f 100644
--- a/src/features/tabs/tabs.ts
+++ b/src/features/tabs/tabs.ts
@@ -27,6 +27,17 @@ export function createTab(state: TabsState, tab: Tab): TabsState {
 	return { tabs, activeConversationId: tab.conversationId };
 }
 
+/**
+ * Add a tab WITHOUT switching the active conversation — used by the
+ * `conversation.open` WS broadcast (CLI `--open`): the tab appears in the
+ * strip but the user stays on their current tab. No-op if already open.
+ */
+export function openTab(state: TabsState, tab: Tab): TabsState {
+	const exists = state.tabs.some((t) => t.conversationId === tab.conversationId);
+	if (exists) return state;
+	return { tabs: [...state.tabs, tab], activeConversationId: state.activeConversationId };
+}
+
 export function selectTab(state: TabsState, conversationId: string): TabsState {
 	return { ...state, activeConversationId: conversationId };
 }