feat: add /list, /who, /whois commands + CLI parity

- Server: add LIST, WHO, WHOIS command handlers in dispatchCommand
  with proper IRC numerics (322/323, 352/315, 311/312/319/318)
- SPA: add /list, /who, /whois command parsing and numeric display
- CLI: add /motd, /who, /whois commands for feature parity
- Rebuild SPA dist from source

internal/handlers/api.go

@@ -670,20 +670,12 @@ func (hdlr *Handlers) dispatchCommand(
 		hdlr.handleQuit(
 			writer, request, sessionID, nick, body,
 		)
-	case "MOTD":
-		hdlr.deliverMOTD(
-			request, clientID, sessionID, nick,
+	case "MOTD", "LIST", "WHO", "WHOIS", "PING":
+		hdlr.dispatchInfoCommand(
+			writer, request,
+			sessionID, clientID, nick,
+			command, target, bodyLines,
 		)
-		hdlr.respondJSON(writer, request,
-			map[string]string{"status": "ok"},
-			http.StatusOK)
-	case "PING":
-		hdlr.respondJSON(writer, request,
-			map[string]string{
-				"command": "PONG",
-				"from":    hdlr.serverName(),
-			},
-			http.StatusOK)
 	default:
 		hdlr.enqueueNumeric(
 			request.Context(), clientID,
@@ -1398,6 +1390,269 @@ func (hdlr *Handlers) executeTopic(
 		http.StatusOK)
 }
 
+// dispatchInfoCommand handles informational IRC commands
+// that produce server-side numerics (MOTD, LIST, WHO,
+// WHOIS, PING).
+func (hdlr *Handlers) dispatchInfoCommand(
+	writer http.ResponseWriter,
+	request *http.Request,
+	sessionID, clientID int64,
+	nick, command, target string,
+	bodyLines func() []string,
+) {
+	okResp := map[string]string{"status": "ok"}
+
+	switch command {
+	case "MOTD":
+		hdlr.deliverMOTD(
+			request, clientID, sessionID, nick,
+		)
+	case "LIST":
+		hdlr.handleListCmd(
+			request, clientID, sessionID, nick,
+		)
+	case "WHO":
+		hdlr.handleWhoCmd(
+			request, clientID, sessionID, nick,
+			target,
+		)
+	case "WHOIS":
+		hdlr.handleWhoisCmd(
+			request, clientID, sessionID, nick,
+			target, bodyLines,
+		)
+	case "PING":
+		hdlr.respondJSON(writer, request,
+			map[string]string{
+				"command": "PONG",
+				"from":    hdlr.serverName(),
+			},
+			http.StatusOK)
+
+		return
+	}
+
+	hdlr.respondJSON(
+		writer, request, okResp, http.StatusOK,
+	)
+}
+
+// handleListCmd sends RPL_LIST (322) for each channel,
+// then sends 323 to signal the end of the list.
+func (hdlr *Handlers) handleListCmd(
+	request *http.Request,
+	clientID, sessionID int64,
+	nick string,
+) {
+	ctx := request.Context()
+
+	channels, err := hdlr.params.Database.ListAllChannels(
+		ctx,
+	)
+	if err != nil {
+		hdlr.enqueueNumeric(
+			ctx, clientID, "323", nick, nil,
+			"End of /LIST",
+		)
+		hdlr.broker.Notify(sessionID)
+
+		return
+	}
+
+	for _, channel := range channels {
+		memberIDs, _ :=
+			hdlr.params.Database.GetChannelMemberIDs(
+				ctx, channel.ID,
+			)
+
+		count := strconv.Itoa(len(memberIDs))
+		topic := channel.Topic
+
+		if topic == "" {
+			topic = " "
+		}
+
+		hdlr.enqueueNumeric(
+			ctx, clientID, "322", nick,
+			[]string{channel.Name, count}, topic,
+		)
+	}
+
+	hdlr.enqueueNumeric(
+		ctx, clientID, "323", nick, nil,
+		"End of /LIST",
+	)
+	hdlr.broker.Notify(sessionID)
+}
+
+// handleWhoCmd sends RPL_WHOREPLY (352) for each member
+// of the target channel, followed by RPL_ENDOFWHO (315).
+func (hdlr *Handlers) handleWhoCmd(
+	request *http.Request,
+	clientID, sessionID int64,
+	nick, target string,
+) {
+	ctx := request.Context()
+
+	if target == "" {
+		hdlr.enqueueNumeric(
+			ctx, clientID, "461", nick,
+			[]string{"WHO"}, "Not enough parameters",
+		)
+		hdlr.broker.Notify(sessionID)
+
+		return
+	}
+
+	channel := target
+	if !strings.HasPrefix(channel, "#") {
+		channel = "#" + channel
+	}
+
+	chID, err := hdlr.params.Database.GetChannelByName(
+		ctx, channel,
+	)
+	if err != nil {
+		hdlr.enqueueNumeric(
+			ctx, clientID, "315", nick,
+			[]string{channel}, "End of /WHO list",
+		)
+		hdlr.broker.Notify(sessionID)
+
+		return
+	}
+
+	members, err := hdlr.params.Database.ChannelMembers(
+		ctx, chID,
+	)
+	if err == nil {
+		srvName := hdlr.serverName()
+
+		for _, mem := range members {
+			hdlr.enqueueNumeric(
+				ctx, clientID, "352", nick,
+				[]string{
+					channel, mem.Nick, "neoirc",
+					srvName, mem.Nick, "H",
+				},
+				"0 "+mem.Nick,
+			)
+		}
+	}
+
+	hdlr.enqueueNumeric(
+		ctx, clientID, "315", nick,
+		[]string{channel}, "End of /WHO list",
+	)
+	hdlr.broker.Notify(sessionID)
+}
+
+// handleWhoisCmd sends WHOIS reply numerics (311, 312,
+// 319, 318) for the target nick.
+func (hdlr *Handlers) handleWhoisCmd(
+	request *http.Request,
+	clientID, sessionID int64,
+	nick, target string,
+	bodyLines func() []string,
+) {
+	ctx := request.Context()
+
+	whoisNick := target
+	if whoisNick == "" {
+		lines := bodyLines()
+		if len(lines) > 0 {
+			whoisNick = strings.TrimSpace(lines[0])
+		}
+	}
+
+	if whoisNick == "" {
+		hdlr.enqueueNumeric(
+			ctx, clientID, "461", nick,
+			[]string{"WHOIS"}, "Not enough parameters",
+		)
+		hdlr.broker.Notify(sessionID)
+
+		return
+	}
+
+	targetSID, err :=
+		hdlr.params.Database.GetSessionByNick(
+			ctx, whoisNick,
+		)
+	if err != nil {
+		hdlr.enqueueNumeric(
+			ctx, clientID, "401", nick,
+			[]string{whoisNick},
+			"No such nick/channel",
+		)
+		hdlr.enqueueNumeric(
+			ctx, clientID, "318", nick,
+			[]string{whoisNick},
+			"End of /WHOIS list",
+		)
+		hdlr.broker.Notify(sessionID)
+
+		return
+	}
+
+	hdlr.sendWhoisNumerics(
+		ctx, clientID, sessionID, nick,
+		whoisNick, targetSID,
+	)
+}
+
+// sendWhoisNumerics emits 311/312/319/318 for a
+// resolved WHOIS target.
+func (hdlr *Handlers) sendWhoisNumerics(
+	ctx context.Context,
+	clientID, sessionID int64,
+	nick, whoisNick string,
+	targetSID int64,
+) {
+	srvName := hdlr.serverName()
+
+	// 311 RPL_WHOISUSER
+	hdlr.enqueueNumeric(
+		ctx, clientID, "311", nick,
+		[]string{whoisNick, whoisNick, "neoirc", "*"},
+		whoisNick,
+	)
+
+	// 312 RPL_WHOISSERVER
+	hdlr.enqueueNumeric(
+		ctx, clientID, "312", nick,
+		[]string{whoisNick, srvName},
+		srvName,
+	)
+
+	// 319 RPL_WHOISCHANNELS
+	channels, _ := hdlr.params.Database.GetSessionChannels(
+		ctx, targetSID,
+	)
+
+	if len(channels) > 0 {
+		names := make([]string, 0, len(channels))
+
+		for _, chanInfo := range channels {
+			names = append(names, chanInfo.Name)
+		}
+
+		hdlr.enqueueNumeric(
+			ctx, clientID, "319", nick,
+			[]string{whoisNick},
+			strings.Join(names, " "),
+		)
+	}
+
+	// 318 RPL_ENDOFWHOIS
+	hdlr.enqueueNumeric(
+		ctx, clientID, "318", nick,
+		[]string{whoisNick},
+		"End of /WHOIS list",
+	)
+	hdlr.broker.Notify(sessionID)
+}
+
 func (hdlr *Handlers) handleQuit(
 	writer http.ResponseWriter,
 	request *http.Request,