fix: remove premature media file cleanup in channel handlers

Media files (photos, voice, audio, documents) downloaded by channel
handlers were immediately deleted via defer when handleMessage returned.
However, HandleMessage publishes to an async message bus, so the agent
goroutine would attempt to access already-deleted files.

Remove the eager defer cleanup from telegram, discord, slack, and line
channels. Temp files in os.TempDir()/picoclaw_media/ are managed by the
OS temp directory lifecycle.

Fixes media/voice/document processing being non-functional across all
affected channels.

pkg/channels/discord.go

@@ -3,7 +3,6 @@ package channels
 import (
 	"context"
 	"fmt"
-	"os"
 	"strings"
 	"sync"
 	"time"
@@ -210,19 +209,10 @@ func (c *DiscordChannel) handleMessage(s *discordgo.Session, m *discordgo.Messag
 	content := m.Content
 	content = c.stripBotMention(content)
 	mediaPaths := make([]string, 0, len(m.Attachments))
-	localFiles := make([]string, 0, len(m.Attachments))
+	// Note: media files in os.TempDir()/picoclaw_media/ are not cleaned up here
-
+	// because HandleMessage publishes to an async message bus. The consumer
-	// Ensure temp files are cleaned up when function returns
+	// goroutine may still need these files after this function returns.
-	defer func() {
+	// Temp files are managed by OS temp directory lifecycle.
-		for _, file := range localFiles {
-			if err := os.Remove(file); err != nil {
-				logger.DebugCF("discord", "Failed to cleanup temp file", map[string]any{
-					"file":  file,
-					"error": err.Error(),
-				})
-			}
-		}
-	}()
 
 	for _, attachment := range m.Attachments {
 		isAudio := utils.IsAudioFile(attachment.Filename, attachment.ContentType)
@@ -230,8 +220,6 @@ func (c *DiscordChannel) handleMessage(s *discordgo.Session, m *discordgo.Messag
 		if isAudio {
 			localPath := c.downloadAttachment(attachment.URL, attachment.Filename)
 			if localPath != "" {
-				localFiles = append(localFiles, localPath)
-
 				transcribedText := ""
 				if c.transcriber != nil && c.transcriber.IsAvailable() {
 					ctx, cancel := context.WithTimeout(c.getContext(), transcriptionTimeout)

pkg/channels/line.go

@@ -10,7 +10,6 @@ import (
 	"fmt"
 	"io"
 	"net/http"
-	"os"
 	"strings"
 	"sync"
 	"time"
@@ -307,18 +306,10 @@ func (c *LINEChannel) processEvent(event lineEvent) {
 
 	var content string
 	var mediaPaths []string
-	localFiles := []string{}
+	// Note: media files in os.TempDir()/picoclaw_media/ are not cleaned up here
-
+	// because HandleMessage publishes to an async message bus. The consumer
-	defer func() {
+	// goroutine may still need these files after this function returns.
-		for _, file := range localFiles {
+	// Temp files are managed by OS temp directory lifecycle.
-			if err := os.Remove(file); err != nil {
-				logger.DebugCF("line", "Failed to cleanup temp file", map[string]interface{}{
-					"file":  file,
-					"error": err.Error(),
-				})
-			}
-		}
-	}()
 
 	switch msg.Type {
 	case "text":
@@ -330,21 +321,18 @@ func (c *LINEChannel) processEvent(event lineEvent) {
 	case "image":
 		localPath := c.downloadContent(msg.ID, "image.jpg")
 		if localPath != "" {
-			localFiles = append(localFiles, localPath)
 			mediaPaths = append(mediaPaths, localPath)
 			content = "[image]"
 		}
 	case "audio":
 		localPath := c.downloadContent(msg.ID, "audio.m4a")
 		if localPath != "" {
-			localFiles = append(localFiles, localPath)
 			mediaPaths = append(mediaPaths, localPath)
 			content = "[audio]"
 		}
 	case "video":
 		localPath := c.downloadContent(msg.ID, "video.mp4")
 		if localPath != "" {
-			localFiles = append(localFiles, localPath)
 			mediaPaths = append(mediaPaths, localPath)
 			content = "[video]"
 		}

pkg/channels/slack.go

@@ -3,7 +3,6 @@ package channels
 import (
 	"context"
 	"fmt"
-	"os"
 	"strings"
 	"sync"
 	"time"
@@ -232,19 +231,10 @@ func (c *SlackChannel) handleMessageEvent(ev *slackevents.MessageEvent) {
 	content = c.stripBotMention(content)
 
 	var mediaPaths []string
-	localFiles := []string{} // 跟踪需要清理的本地文件
+	// Note: media files in os.TempDir()/picoclaw_media/ are not cleaned up here
-
+	// because HandleMessage publishes to an async message bus. The consumer
-	// 确保临时文件在函数返回时被清理
+	// goroutine may still need these files after this function returns.
-	defer func() {
+	// Temp files are managed by OS temp directory lifecycle.
-		for _, file := range localFiles {
-			if err := os.Remove(file); err != nil {
-				logger.DebugCF("slack", "Failed to cleanup temp file", map[string]interface{}{
-					"file":  file,
-					"error": err.Error(),
-				})
-			}
-		}
-	}()
 
 	if ev.Message != nil && len(ev.Message.Files) > 0 {
 		for _, file := range ev.Message.Files {
@@ -252,7 +242,6 @@ func (c *SlackChannel) handleMessageEvent(ev *slackevents.MessageEvent) {
 			if localPath == "" {
 				continue
 			}
-			localFiles = append(localFiles, localPath)
 			mediaPaths = append(mediaPaths, localPath)
 
 			if utils.IsAudioFile(file.Name, file.Mimetype) && c.transcriber != nil && c.transcriber.IsAvailable() {

pkg/channels/telegram.go

@@ -221,19 +221,10 @@ func (c *TelegramChannel) handleMessage(ctx context.Context, message *telego.Mes
 
 	content := ""
 	mediaPaths := []string{}
-	localFiles := []string{} // 跟踪需要清理的本地文件
+	// Note: media files in os.TempDir()/picoclaw_media/ are not cleaned up here
-
+	// because HandleMessage publishes to an async message bus. The consumer
-	// 确保临时文件在函数返回时被清理
+	// goroutine may still need these files after this function returns.
-	defer func() {
+	// Temp files are managed by OS temp directory lifecycle.
-		for _, file := range localFiles {
-			if err := os.Remove(file); err != nil {
-				logger.DebugCF("telegram", "Failed to cleanup temp file", map[string]interface{}{
-					"file":  file,
-					"error": err.Error(),
-				})
-			}
-		}
-	}()
 
 	if message.Text != "" {
 		content += message.Text
@@ -250,7 +241,6 @@ func (c *TelegramChannel) handleMessage(ctx context.Context, message *telego.Mes
 		photo := message.Photo[len(message.Photo)-1]
 		photoPath := c.downloadPhoto(ctx, photo.FileID)
 		if photoPath != "" {
-			localFiles = append(localFiles, photoPath)
 			mediaPaths = append(mediaPaths, photoPath)
 			if content != "" {
 				content += "\n"
@@ -262,7 +252,6 @@ func (c *TelegramChannel) handleMessage(ctx context.Context, message *telego.Mes
 	if message.Voice != nil {
 		voicePath := c.downloadFile(ctx, message.Voice.FileID, ".ogg")
 		if voicePath != "" {
-			localFiles = append(localFiles, voicePath)
 			mediaPaths = append(mediaPaths, voicePath)
 
 			transcribedText := ""
@@ -297,7 +286,6 @@ func (c *TelegramChannel) handleMessage(ctx context.Context, message *telego.Mes
 	if message.Audio != nil {
 		audioPath := c.downloadFile(ctx, message.Audio.FileID, ".mp3")
 		if audioPath != "" {
-			localFiles = append(localFiles, audioPath)
 			mediaPaths = append(mediaPaths, audioPath)
 			if content != "" {
 				content += "\n"
@@ -309,7 +297,6 @@ func (c *TelegramChannel) handleMessage(ctx context.Context, message *telego.Mes
 	if message.Document != nil {
 		docPath := c.downloadFile(ctx, message.Document.FileID, "")
 		if docPath != "" {
-			localFiles = append(localFiles, docPath)
 			mediaPaths = append(mediaPaths, docPath)
 			if content != "" {
 				content += "\n"