fix: Strip bot self-mention in Discord responses and remove AGENTS.md from summoning modal

Discord: include sender's mention format in [From:] annotation so models
use the correct user ID, and strip the bot's own @mention from message
content to prevent the model from echoing it back.

Summoning modal: remove AGENTS.md from progress list since backend only
generates SOUL.md and IDENTITY.md.

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

internal/channels/discord/discord.go

@@ -4,6 +4,7 @@ import (
 	"context"
 	"fmt"
 	"log/slog"
+	"strings"
 	"sync"
 	"time"
 
@@ -330,10 +331,14 @@ func (c *Channel) handleMessage(_ *discordgo.Session, m *discordgo.MessageCreate
 		c.placeholders.Store(m.ID, placeholder.ID)
 	}
 
+	// Strip bot @mention from content — it's just the trigger, not meaningful.
+	content = strings.ReplaceAll(content, "<@"+c.botUserID+">", "")
+	content = strings.TrimSpace(content)
+
 	// Build final content with group context.
 	finalContent := content
 	if peerKind == "group" {
-		annotated := fmt.Sprintf("[From: %s]\n%s", senderName, content)
+		annotated := fmt.Sprintf("[From: %s (<@%s>)]\n%s", senderName, senderID, content)
 		if c.historyLimit > 0 {
 			finalContent = c.groupHistory.BuildContext(channelID, annotated, c.historyLimit)
 		} else {

ui/web/src/pages/agents/summoning-modal.tsx

@@ -21,7 +21,6 @@ interface SummoningModalProps {
 const SUMMONING_FILES = [
   { name: "SOUL.md", label: "Soul & Personality" },
   { name: "IDENTITY.md", label: "Identity Card" },
-  { name: "AGENTS.md", label: "Operating Instructions" },
 ];
 
 export function SummoningModal({