Add 'View packet' link in channel chat messages

Include packetId in channel message API response, render as link
in message metadata row that navigates to #/packets/id/<id>.

public/channels.js

@@ -398,7 +398,7 @@
         <div class="ch-msg-content">
           <div class="ch-msg-sender ch-sender-link ch-tappable" style="color:${senderColor}" data-node="${safeId}">${escapeHtml(sender)}</div>
           <div class="ch-msg-bubble">${displayText}</div>
-          <div class="ch-msg-meta">${meta.join(' · ')}</div>
+          <div class="ch-msg-meta">${meta.join(' · ')}${msg.packetId ? ` · <a href="#/packets/id/${msg.packetId}" class="ch-analyze-link">View packet →</a>` : ''}</div>
         </div>
       </div>`;
     }).join('');

server.js

@@ -994,6 +994,7 @@ app.get('/api/channels/:hash/messages', (req, res) => {
         encrypted: !decoded.text && !decoded.sender,
         timestamp: pkt.timestamp,
         sender_timestamp: decoded.sender_timestamp || null,
+        packetId: pkt.id,
         repeats: 1,
         observers: [pkt.observer_name || pkt.observer_id].filter(Boolean),
         hops: decoded.path_len || (pkt.path_json ? JSON.parse(pkt.path_json).length : 0),