fix: compact timestamps, historical alias resolution, wider ts column

- Timestamps now show "Jun 28 10:58" for older messages (dropped
  "Yesterday" which overflowed the fixed-width column)
- Timestamp column widened from 52px to 72px to fit date+time
- state_snapshot now includes known_peers (historically seen, not
  currently connected) so the UI can resolve aliases in history
- MessagePane aliasFor falls back to knownPeers map

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

internal/ipc/ipc.go

@@ -459,6 +459,22 @@ func stateSnapshot(mgr *netmgr.Manager) proto.IpcMessage {
 				msg.Rooms = append(msg.Rooms, r)
 			}
 		}
+		// Include all historically-known peers so the UI can resolve aliases in history.
+		if known, err := all[0].Store.KnownPeers(); err == nil {
+			connected := map[proto.PeerID]bool{}
+			for _, p := range msg.ConnectedPeers {
+				connected[p.ID] = true
+			}
+			for id, alias := range known {
+				if connected[id] {
+					continue // already in ConnectedPeers
+				}
+				msg.KnownPeers = append(msg.KnownPeers, proto.PeerInfo{
+					ID:    id,
+					Alias: alias,
+				})
+			}
+		}
 	}
 
 	return msg