feat(chat): delivery ticks on the last message in the chat list (#3)

Conversations DTO now returns last_status (sent/delivered/read for DMs; sent for groups) for
my last message. The list row shows the matching tick (single/double, blue when read) and a
red 'Draft:' indicator when there's unsent text. Live 'sent' on send/receive; upgrades to
delivered/read on refresh. e2e 119.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

server/routes.js

@@ -684,6 +684,7 @@ route('GET', '/api/messages/conversations', async (req, res) => {
     kind: 'dm', id: c.other, contactId: c.other, name: names[c.other] || 'Unknown', online: CHAT.isOnline(c.other), avatar: avatars[c.other] || null,
     callActive: !!dc, callRoom: dc ? dc.room : null, favorite: favs.has('dm:' + c.other), status: inCall.has(c.other) ? 'incall' : (statuses[c.other] || 'active'),
     last_body: c.last.body || (c.last.attachment_id ? '📎 Attachment' : ''), last_at: c.last.created_at, last_from_me: c.last.sender_id === u.id, unread: c.unread,
+    last_status: c.last.sender_id === u.id ? (c.last.read_at ? 'read' : (c.last.delivered_at ? 'delivered' : 'sent')) : null, // tick for my last message
   }; });
   // Groups
   const groupItems = R.conversations.listForUser(u.team_id, u.id).map((g) => {
@@ -694,6 +695,7 @@ route('GET', '/api/messages/conversations', async (req, res) => {
       callActive: groupCalls.has(g.id), callRoom: (groupCalls.get(g.id) || {}).room || null,
       last_body: last ? (last.body || (last.attachment_id ? '📎 Attachment' : '')) : '', last_at: last ? last.created_at : g.created_at,
       last_from_me: last ? last.sender_id === u.id : false, unread: last ? R.messages.unreadInConversation(g.id, u.id, since) : 0,
+      last_status: (last && last.sender_id === u.id) ? 'sent' : null, // groups: simple sent tick (per-member receipts aren't tracked here)
     };
   });
   json(res, 200, [...dmItems, ...groupItems].sort((a, b) => b.last_at - a.last_at));