fix: remove premature cleanup from onebot, fix discord audio file leak

- Remove defer cleanup of LocalFiles in onebot channel handler, same
  async race condition as the other channels.
- Remove the now-unused LocalFiles field from parseMessageResult.
- Add downloaded audio files to mediaPaths in discord channel so they
  are tracked (previously only tracked via the now-removed localFiles).

pkg/channels/discord.go

@@ -220,6 +220,7 @@ func (c *DiscordChannel) handleMessage(s *discordgo.Session, m *discordgo.Messag
 		if isAudio {
 			localPath := c.downloadAttachment(attachment.URL, attachment.Filename)
 			if localPath != "" {
+				mediaPaths = append(mediaPaths, localPath)
 				transcribedText := ""
 				if c.transcriber != nil && c.transcriber.IsAvailable() {
 					ctx, cancel := context.WithTimeout(c.getContext(), transcriptionTimeout)

pkg/channels/onebot.go

@@ -4,7 +4,6 @@ import (
 	"context"
 	"encoding/json"
 	"fmt"
-	"os"
 	"strconv"
 	"strings"
 	"sync"
@@ -570,9 +569,8 @@ func parseJSONString(raw json.RawMessage) string {
 type parseMessageResult struct {
 	Text           string
 	IsBotMentioned bool
-	Media          []string
-	LocalFiles     []string
-	ReplyTo        string
+	Media   []string
+	ReplyTo string
 }
 
 func (c *OneBotChannel) parseMessageSegments(raw json.RawMessage, selfID int64) parseMessageResult {
@@ -603,7 +601,6 @@ func (c *OneBotChannel) parseMessageSegments(raw json.RawMessage, selfID int64)
 	mentioned := false
 	selfIDStr := strconv.FormatInt(selfID, 10)
 	var media []string
-	var localFiles []string
 	var replyTo string
 
 	for _, seg := range segments {
@@ -642,7 +639,6 @@ func (c *OneBotChannel) parseMessageSegments(raw json.RawMessage, selfID int64)
 					})
 					if localPath != "" {
 						media = append(media, localPath)
-						localFiles = append(localFiles, localPath)
 						textParts = append(textParts, fmt.Sprintf("[%s]", segType))
 					}
 				}
@@ -656,7 +652,6 @@ func (c *OneBotChannel) parseMessageSegments(raw json.RawMessage, selfID int64)
 						LoggerPrefix: "onebot",
 					})
 					if localPath != "" {
-						localFiles = append(localFiles, localPath)
 						if c.transcriber != nil && c.transcriber.IsAvailable() {
 							tctx, tcancel := context.WithTimeout(c.ctx, 30*time.Second)
 							result, err := c.transcriber.Transcribe(tctx, localPath)
@@ -702,9 +697,8 @@ func (c *OneBotChannel) parseMessageSegments(raw json.RawMessage, selfID int64)
 	return parseMessageResult{
 		Text:           strings.TrimSpace(strings.Join(textParts, "")),
 		IsBotMentioned: mentioned,
-		Media:          media,
-		LocalFiles:     localFiles,
-		ReplyTo:        replyTo,
+		Media:   media,
+		ReplyTo: replyTo,
 	}
 }
 
@@ -824,19 +818,10 @@ func (c *OneBotChannel) handleMessage(raw *oneBotRawEvent) {
 		}
 	}
 
-	// Clean up temp files when done
-	if len(parsed.LocalFiles) > 0 {
-		defer func() {
-			for _, f := range parsed.LocalFiles {
-				if err := os.Remove(f); err != nil {
-					logger.DebugCF("onebot", "Failed to remove temp file", map[string]interface{}{
-						"path":  f,
-						"error": err.Error(),
-					})
-				}
-			}
-		}()
-	}
+	// Note: media files in os.TempDir()/picoclaw_media/ are not cleaned up here
+	// because HandleMessage publishes to an async message bus. The consumer
+	// goroutine may still need these files after this function returns.
+	// Temp files are managed by OS temp directory lifecycle.
 
 	if c.isDuplicate(messageID) {
 		logger.DebugCF("onebot", "Duplicate message, skipping", map[string]interface{}{