feat(messages): optimistic UI — message appears instantly on Enter

Instead of waiting for API response before showing the message,
the editor clears and message appears in DOM immediately. The API
call happens in the background. Real message ID replaces temp ID
in state for polling dedup.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

CLAUDE.md

@@ -104,7 +104,7 @@ Na serwerze .249 nginx na porcie 80 przekierowuje na HTTPS. Flask/Gunicorn na po
 git push origin master && git push inpi master
 
 # 2. STAGING: Wdrożenie i test
-ssh maciejpi@10.22.68.248 "cd /var/www/nordabiznes && sudo -u www-data git pull && sudo systemctl restart nordabiznes"
+ssh maciejpi@10.22.68.248 "cd /var/www/nordabiznes && sudo -u www-data git pull && sudo systemctl reload nordabiznes"
 # ⚠️ OBOWIĄZKOWO: Test manualny nowej funkcjonalności na staging!
 
 # 3. PROD: Pull zmiany (DOPIERO PO WERYFIKACJI STAGING!)
@@ -114,7 +114,7 @@ ssh maciejpi@10.22.68.249 "cd /var/www/nordabiznes && sudo -u www-data git pull"
 ssh maciejpi@10.22.68.249 "cd /var/www/nordabiznes && /var/www/nordabiznes/venv/bin/python3 scripts/run_migration.py database/migrations/XXX_nazwa.sql"
 
 # 5. PROD: Restart + weryfikacja
-ssh maciejpi@10.22.68.249 "sudo systemctl restart nordabiznes"
+ssh maciejpi@10.22.68.249 "sudo systemctl reload nordabiznes"
 curl -sI https://nordabiznes.pl/health | head -3
 ```
 
@@ -158,7 +158,7 @@ ssh maciejpi@10.22.68.249 "source .env && python3 skrypt.py"
 ### Deployment
 - Przed wdrożeniem: `python -m py_compile app.py`
 - SSH: `ssh maciejpi@10.22.68.249` (ZAWSZE jako maciejpi!)
-- Ścieżka: `/var/www/nordabiznes` | Restart: `sudo systemctl restart nordabiznes`
+- Ścieżka: `/var/www/nordabiznes` | Restart: `sudo systemctl reload nordabiznes`
 - **ZAWSZE** aktualizuj `release_notes` w app.py
 
 ### Szablony Jinja2 - WAŻNE!

static/js/conversations.js

@@ -1275,28 +1275,51 @@
                 return;
             }
             var convId = state.currentConversationId;
+            var savedReplyTo = state.replyToMessage;
+            var savedFiles = state.attachedFiles.slice();
+
+            // OPTIMISTIC UI: clear editor and show message IMMEDIATELY
+            state.quill.setText('');
+            state.attachedFiles = [];
+            state.replyToMessage = null;
+            var replyPreview = document.getElementById('replyPreview');
+            if (replyPreview) replyPreview.style.display = 'none';
+            Composer.renderAttachments();
+
+            // Show optimistic message in DOM instantly
+            var tempId = 'temp-' + Date.now();
+            var optimisticMsg = {
+                id: tempId,
+                conversation_id: convId,
+                content: html,
+                sender_id: window.__CURRENT_USER__ ? window.__CURRENT_USER__.id : null,
+                sender: window.__CURRENT_USER__ || {},
+                created_at: new Date().toISOString(),
+                _optimistic: true
+            };
+            ChatView.appendMessage(optimisticMsg);
 
             try {
                 var fd = new FormData();
                 if (html && text) fd.append('content', html);
-                if (state.replyToMessage) fd.append('reply_to_id', state.replyToMessage.id);
+                if (savedReplyTo) fd.append('reply_to_id', savedReplyTo.id);
 
-                state.attachedFiles.forEach(function (file) {
+                savedFiles.forEach(function (file) {
                     fd.append('files', file);
                 });
 
                 var result = await api('/api/conversations/' + convId + '/messages', 'POST', fd);
 
-                // Clear editor
-                state.quill.setText('');
-                state.attachedFiles = [];
-                state.replyToMessage = null;
-                var replyPreview = document.getElementById('replyPreview');
-                if (replyPreview) replyPreview.style.display = 'none';
-                Composer.renderAttachments();
-
-                // Append the sent message (dedup check inside appendMessage)
-                ChatView.appendMessage(result);
+                // Replace temp ID with real ID in state so polling dedup works
+                var msgs = state.messages[convId];
+                if (msgs) {
+                    for (var i = msgs.length - 1; i >= 0; i--) {
+                        if (msgs[i].id === tempId) {
+                            msgs[i] = result;
+                            break;
+                        }
+                    }
+                }
 
                 // Update conversation in list
                 ConversationList.updateConversation(convId, {