feat(14-01): render attachment messages with distinct styling and metadata

- Import formatFileSize from attachmentValidation service
- Add isAttachmentMessage helper to detect attachment messages
- Render attachment messages with light blue background (#e3f2fd)
- Display paperclip icon with accessible aria-label
- Show '[name] attached [filename]' format with file size if available
- Update PropTypes to include optional attachment fields
- Maintain React.memo for performance

jam-ui/src/components/client/chat/JKChatMessage.js

@@ -1,6 +1,7 @@
 import React from 'react';
 import PropTypes from 'prop-types';
 import { formatTimestamp } from '../../../utils/formatTimestamp';
+import { formatFileSize } from '../../../services/attachmentValidation';
 
 /**
  * Get initials for avatar from sender name
@@ -8,67 +9,120 @@ import { formatTimestamp } from '../../../utils/formatTimestamp';
  * @param {string} name - Sender name
  * @returns {string} Initials (e.g., "JD" for "John Doe")
  */
-const getInitials = (name) => {
+const getInitials = name => {
   if (!name) return '?';
   const parts = name.trim().split(' ');
   if (parts.length === 1) return parts[0][0].toUpperCase();
   return (parts[0][0] + parts[parts.length - 1][0]).toUpperCase();
 };
 
+/**
+ * Check if message is an attachment
+ * @param {Object} message - Message object
+ * @returns {boolean} True if message has attachment
+ */
+const isAttachmentMessage = message => {
+  return message.attachmentId && message.attachmentName;
+};
+
 /**
  * JKChatMessage - Individual message display component
  *
  * Displays a single chat message with avatar, sender name, message text, and timestamp.
+ * Supports attachment messages with distinct styling and metadata display.
  *
  * Features:
  * - Avatar with initials (first + last name)
  * - Sender name in bold
  * - Relative timestamp (via formatTimestamp utility)
  * - Message text with word wrapping
+ * - Attachment display with paperclip icon, filename, and size
  * - React.memo for performance optimization
  */
 const JKChatMessage = ({ message }) => {
-  const { senderName, message: text, createdAt } = message;
+  const { senderName, message: text, createdAt, attachmentName, attachmentSize } = message;
 
-  return (
-    <div style={{
+  // Common avatar style
+  const avatarStyle = {
+    width: '36px',
+    height: '36px',
+    borderRadius: '50%',
+    backgroundColor: '#007bff',
+    color: 'white',
+    display: 'flex',
+    alignItems: 'center',
+    justifyContent: 'center',
+    fontWeight: 'bold',
+    fontSize: '14px',
+    flexShrink: 0
+  };
+
+  // Attachment message styling
+  if (isAttachmentMessage(message)) {
+    const attachmentStyle = {
       display: 'flex',
       gap: '12px',
       marginBottom: '16px',
       padding: '8px',
       borderRadius: '4px',
-      backgroundColor: '#f8f9fa'
-    }}>
-      {/* Avatar */}
-      <div style={{
-        width: '36px',
-        height: '36px',
-        borderRadius: '50%',
-        backgroundColor: '#007bff',
-        color: 'white',
-        display: 'flex',
-        alignItems: 'center',
-        justifyContent: 'center',
-        fontWeight: 'bold',
-        fontSize: '14px',
-        flexShrink: 0
-      }}>
-        {getInitials(senderName)}
+      backgroundColor: '#e3f2fd',
+      border: '1px solid #bbdefb'
+    };
+
+    const fileIconStyle = {
+      fontSize: '16px',
+      marginRight: '4px'
+    };
+
+    return (
+      <div style={attachmentStyle}>
+        {/* Avatar */}
+        <div style={avatarStyle}>{getInitials(senderName)}</div>
+
+        {/* Attachment content */}
+        <div style={{ flex: 1, minWidth: 0 }}>
+          <div style={{ display: 'flex', alignItems: 'baseline', gap: '8px', marginBottom: '4px' }}>
+            <span style={{ fontWeight: 600, fontSize: '14px', color: '#212529' }}>{senderName || 'Unknown'}</span>
+            <span style={{ fontSize: '12px', color: '#6c757d' }}>{formatTimestamp(createdAt)}</span>
+          </div>
+          <div style={{ fontSize: '14px', color: '#212529', display: 'flex', alignItems: 'center' }}>
+            <span style={fileIconStyle} role="img" aria-label="attachment">
+              📎
+            </span>
+            <span>
+              attached <strong>{attachmentName}</strong>
+              {attachmentSize && (
+                <span style={{ color: '#6c757d', marginLeft: '4px' }}>({formatFileSize(attachmentSize)})</span>
+              )}
+            </span>
+          </div>
+        </div>
       </div>
+    );
+  }
+
+  // Regular text message
+  return (
+    <div
+      style={{
+        display: 'flex',
+        gap: '12px',
+        marginBottom: '16px',
+        padding: '8px',
+        borderRadius: '4px',
+        backgroundColor: '#f8f9fa'
+      }}
+    >
+      {/* Avatar */}
+      <div style={avatarStyle}>{getInitials(senderName)}</div>
 
       {/* Message content */}
       <div style={{ flex: 1, minWidth: 0 }}>
         <div style={{ display: 'flex', alignItems: 'baseline', gap: '8px', marginBottom: '4px' }}>
-          <span style={{ fontWeight: 600, fontSize: '14px', color: '#212529' }}>
-            {senderName || 'Unknown'}
-          </span>
-          <span style={{ fontSize: '12px', color: '#6c757d' }}>
-            {formatTimestamp(createdAt)}
-          </span>
-        </div>
-        <div style={{ fontSize: '14px', color: '#212529', wordWrap: 'break-word' }}>
-          {text}
+          <span style={{ fontWeight: 600, fontSize: '14px', color: '#212529' }}>{senderName || 'Unknown'}</span>
+          <span style={{ fontSize: '12px', color: '#6c757d' }}>{formatTimestamp(createdAt)}</span>
         </div>
+        <div style={{ fontSize: '14px', color: '#212529', wordWrap: 'break-word' }}>{text}</div>
       </div>
     </div>
   );
@@ -79,8 +133,14 @@ JKChatMessage.propTypes = {
     id: PropTypes.string.isRequired,
     senderId: PropTypes.string.isRequired,
     senderName: PropTypes.string,
-    message: PropTypes.string.isRequired,
-    createdAt: PropTypes.string.isRequired
+    message: PropTypes.string, // Optional for attachment-only messages
+    createdAt: PropTypes.string.isRequired,
+    // Attachment fields (optional)
+    attachmentId: PropTypes.string,
+    attachmentName: PropTypes.string,
+    attachmentType: PropTypes.oneOf(['notation', 'audio']),
+    purpose: PropTypes.string,
+    attachmentSize: PropTypes.number
   }).isRequired
 };