feat(messages): read receipts in group chat, fix group_manage 500 error

- Show small avatars under each message indicating who has read up to that point
- Fix BuildError: group_update → group_edit in group_manage template

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

blueprints/messages/group_routes.py

@@ -268,6 +268,26 @@ def group_view(group_id):
             MessageGroupMember.group_id == group_id
         ).order_by(MessageGroupMember.role, MessageGroupMember.joined_at).all()
 
+        # Build read receipts: for each message, find who has read up to that point
+        # Show avatar at the LAST message they've read (like Teams/WhatsApp)
+        read_receipts = {}  # message_id -> list of (user, avatar_path)
+        if messages:
+            other_members = [m for m in members if m.user_id != current_user.id]
+            for m in other_members:
+                if not m.last_read_at:
+                    continue
+                # Find the last message this member has read
+                last_read_msg = None
+                for msg in messages:
+                    if msg.created_at <= m.last_read_at:
+                        last_read_msg = msg
+                    else:
+                        break
+                if last_read_msg:
+                    if last_read_msg.id not in read_receipts:
+                        read_receipts[last_read_msg.id] = []
+                    read_receipts[last_read_msg.id].append(m.user)
+
         # Mark as read
         membership.last_read_at = datetime.now()
         db.commit()
@@ -276,7 +296,8 @@ def group_view(group_id):
             group=group,
             messages=messages,
             members=members,
-            membership=membership
+            membership=membership,
+            read_receipts=read_receipts
         )
     finally:
         db.close()

templates/messages/group_manage.html

@@ -350,7 +350,7 @@
     {% if membership.is_owner %}
     <div class="manage-card">
         <h2>Informacje o grupie</h2>
-        <form method="POST" action="{{ url_for('messages.group_update', group_id=group.id) }}">
+        <form method="POST" action="{{ url_for('messages.group_edit', group_id=group.id) }}">
             <input type="hidden" name="csrf_token" value="{{ csrf_token() }}">
             <div class="form-group">
                 <label for="group-name">Nazwa grupy</label>

templates/messages/group_view.html

@@ -267,6 +267,42 @@
         font-size: var(--font-size-sm);
     }
 
+    /* Read receipts */
+    .msg-read-receipts {
+        display: flex;
+        gap: 2px;
+        justify-content: flex-end;
+        margin-top: 4px;
+        padding-right: 4px;
+    }
+
+    .read-receipt {
+        width: 20px;
+        height: 20px;
+        border-radius: 50%;
+        overflow: hidden;
+        flex-shrink: 0;
+    }
+
+    .read-receipt img {
+        width: 100%;
+        height: 100%;
+        object-fit: cover;
+    }
+
+    .read-receipt span {
+        width: 20px;
+        height: 20px;
+        display: flex;
+        align-items: center;
+        justify-content: center;
+        background: var(--primary);
+        color: white;
+        font-size: 10px;
+        font-weight: 600;
+        border-radius: 50%;
+    }
+
     /* Reply form */
     .reply-section {
         background: var(--surface);
@@ -417,6 +453,19 @@
                     </div>
                     {% endif %}
                 </div>
+                {% if read_receipts and read_receipts.get(msg.id) %}
+                <div class="msg-read-receipts">
+                    {% for reader in read_receipts[msg.id] %}
+                    <div class="read-receipt" title="{{ reader.name or reader.email.split('@')[0] }}">
+                        {% if reader.avatar_path %}
+                        <img src="{{ url_for('static', filename=reader.avatar_path) }}" alt="">
+                        {% else %}
+                        <span>{{ (reader.name or reader.email)[0].upper() }}</span>
+                        {% endif %}
+                    </div>
+                    {% endfor %}
+                </div>
+                {% endif %}
             </div>
             {% endfor %}
         {% else %}