Fix non-cache refresh on unfocused active threads; doc and test improvements

frontend/src/App.tsx

@@ -307,10 +307,20 @@ export function App() {
       onContactDeleted: (publicKey: string) => {
         setContacts((prev) => prev.filter((c) => c.public_key !== publicKey));
         messageCache.remove(publicKey);
+        const active = activeConversationRef.current;
+        if (active?.type === 'contact' && active.id === publicKey) {
+          pendingDeleteFallbackRef.current = true;
+          setActiveConversation(null);
+        }
       },
       onChannelDeleted: (key: string) => {
         setChannels((prev) => prev.filter((c) => c.key !== key));
         messageCache.remove(key);
+        const active = activeConversationRef.current;
+        if (active?.type === 'channel' && active.id === key) {
+          pendingDeleteFallbackRef.current = true;
+          setActiveConversation(null);
+        }
       },
       onRawPacket: (packet: RawPacket) => {
         setRawPackets((prev) => appendRawPacketUnique(prev, packet, MAX_RAW_PACKETS));
@@ -331,6 +341,7 @@ export function App() {
       setConfig,
       activeConversationRef,
       hasNewerMessagesRef,
+      setActiveConversation,
       setContacts,
       setChannels,
       triggerReconcile,

frontend/src/messageCache.ts

@@ -76,6 +76,9 @@ export function addMessage(id: string, msg: Message, contentKey: string): boolea
       .sort((a, b) => b.received_at - a.received_at)
       .slice(0, MAX_MESSAGES_PER_ENTRY);
   }
+  // Promote to MRU so actively-messaged conversations aren't evicted
+  cache.delete(id);
+  cache.set(id, entry);
   return true;
 }
 

frontend/src/test/messageCache.test.ts

@@ -239,6 +239,23 @@ describe('messageCache', () => {
       expect(entry!.seenContent.has('CHAN-channel123-First contact-1700000000')).toBe(true);
     });
 
+    it('promotes entry to MRU on addMessage', () => {
+      // Fill cache to capacity
+      for (let i = 0; i < MAX_CACHED_CONVERSATIONS; i++) {
+        messageCache.set(`conv${i}`, createEntry([createMessage({ id: i })]));
+      }
+
+      // addMessage to conv0 (currently LRU) should promote it
+      const msg = createMessage({ id: 999, text: 'Incoming WS message' });
+      messageCache.addMessage('conv0', msg, 'CHAN-channel123-Incoming WS message-1700000000');
+
+      // Add one more — conv1 should now be LRU and get evicted, not conv0
+      messageCache.set('conv_new', createEntry());
+
+      expect(messageCache.get('conv0')).toBeDefined(); // Was promoted by addMessage
+      expect(messageCache.get('conv1')).toBeUndefined(); // Was LRU, evicted
+    });
+
     it('returns false for duplicate delivery to auto-created entry', () => {
       const msg = createMessage({ id: 10, text: 'Echo' });
       const contentKey = 'CHAN-channel123-Echo-1700000000';