Keep messages and inbox activity that arrive during recovery fetches.
Queue another snapshot when live updates make unread counts ambiguous.

Invalidate inbox work on destruction and stop delayed missing-chat
requests from restarting fetches or invoking callbacks after sign-out.

Add regressions for these races and keep Chromium shadow compositing
consistent in the browser screenshot comparisons.

@@ -10,3 +10,3 @@
 	dim: '[data-slot="live-stack-dim"]',
 };
-const NO_EDGE = "0 0 #0000";
+const NO_EDGE = "-1px 0 0 rgb(255 255 255 / 0.001)";

@@ -185,3 +185,3 @@
 
 		if (this.#seenMessages.has(message.messageId)) {
-			if (!this.#isActive(conversationId))
+			if (conversationId !== this.#activeConversationId)

@@ -222,3 +223,3 @@
-		const isInboxPageRoot = page.route.id === "/(protected)/chat";
-		const twoColLayout = !singleColumnLayout.current;
-		const isConversationsListVisible = isInboxPageRoot || twoColLayout;
+		const isConversationsListVisible =
+			page.route.id === "/(protected)/chat" ||
+			!singleColumnLayout.current;

@@ -278,3 +282,1 @@
-			const windowFloor = reachedEnd
-				? Number.NEGATIVE_INFINITY
-				: oldestFetchedTs;
+			const windowFloor = reachedEnd ? -Infinity : oldestFetchedTs;

@@ -334,3 +342,1 @@
-	}: {
-		errorLabel?: string;
-	}): Promise<boolean> {
+	async #runSyncLatest(args: { errorLabel?: string }): Promise<boolean> {

@@ -436,3 +443,1 @@
-		const joinedSyncWasTooEarly =
-			joinedRunningSync && syncSucceeded && !this.#find(id);
-		if (joinedSyncWasTooEarly) await this.ensureLoaded(id);
+		if (joinedRunningSync && syncSucceeded && !this.#find(id))

@@ -606,3 +607,1 @@
-		return this.entries.find(
-			(e) => e.data.conversationId === conversationId,
-		);
+	#find(id: string): Conversation | undefined {

@@ -618,3 +611,5 @@
-		const { conversationId } = incoming.data;
-		this.#readRequests.noteSnapshot(conversationId);
-		mergeConversation({
+	#mergeIncoming(
+		existing: Conversation,
+		incoming: Conversation,
+		atStart: Map<string, number>,
+	): void {

@@ -7,16 +7,29 @@ export function mergeConversation({
 	existing,
 	incoming,
 	pendingFlags,
+	lastActivityAtFetchStart = existing.data.lastActivityTimestamp,

@@ -242,3 +243,1 @@
-				this.#syncCache();
-				return;
-			}
+			if (!changed) return this.#syncCache();

@@ -144,15 +144,18 @@ export function sentMessages(
 export function mergeServerMessages({
 	local,
 	server,
+	localIdsAtFetchStart = local.map((m) => m.messageId),