fix(messages): capture content in keydown, clear editor instantly, send async

Root cause: when typing fast + Enter, previous send hadn't finished
clearing the editor, so new text accumulated. Fix: keydown handler
captures content snapshot and clears Quill SYNCHRONOUSLY, then sends
via sendContent(). No setTimeout, no race condition.

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

static/js/conversations.js

@@ -1225,12 +1225,18 @@
                 },
             });
 
-            // Enter = send (tiny delay lets Quill commit pending keystrokes)
+            // Enter = send: capture content immediately, clear editor, send async
             state.quill.root.addEventListener('keydown', function (e) {
                 if (e.key === 'Enter' && !e.shiftKey) {
                     e.preventDefault();
                     e.stopImmediatePropagation();
-                    setTimeout(function() { Composer.send(); }, 10);
+                    // Snapshot content NOW before Quill processes further keystrokes
+                    var html = state.quill.root.innerHTML;
+                    var text = state.quill.getText().trim();
+                    if (text) {
+                        state.quill.setText(''); // Clear immediately
+                        Composer.sendContent(html, text); // Send with captured content
+                    }
                 }
             }, true);
 
@@ -1271,23 +1277,36 @@
             }
         },
 
-        send: async function () {
+        // sendContent: called with pre-captured content (from Enter keydown)
-            if (!state.currentConversationId || !state.quill) return;
+        sendContent: async function (html, text) {
-            if (state._isSending) return;
+            if (!state.currentConversationId) return;
-            state._isSending = true;
+            var convId = state.currentConversationId;
-
+            var savedReplyTo = state.replyToMessage;
-            var html = state.quill.root.innerHTML;
+            var savedFiles = state.attachedFiles.slice();
-            var text = state.quill.getText().trim();
+
-
+            // Clear state (editor already cleared by keydown handler)
-            if (!text && !state.attachedFiles.length) {
+            state.attachedFiles = [];
-                state._isSending = false;
+            state.replyToMessage = null;
-                return;
+            var replyPreview = document.getElementById('replyPreview');
-            }
+            if (replyPreview) replyPreview.style.display = 'none';
+            Composer.renderAttachments();
+
+            return Composer._doSend(convId, html, text, savedReplyTo, savedFiles);
+        },
+
+        // send: called from button click — reads from Quill
+        send: async function () {
+            if (!state.currentConversationId || !state.quill) return;
+
+            var html = state.quill.root.innerHTML;
+            var text = state.quill.getText().trim();
+
+            if (!text && !state.attachedFiles.length) 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;
@@ -1295,6 +1314,11 @@
             if (replyPreview) replyPreview.style.display = 'none';
             Composer.renderAttachments();
 
+            return Composer._doSend(convId, html, text, savedReplyTo, savedFiles);
+        },
+
+        _doSend: async function (convId, html, text, savedReplyTo, savedFiles) {
+
             // Show optimistic message in DOM instantly
             var tempId = 'temp-' + Date.now();
             var optimisticMsg = {