fix(channels): extract and download images from Lark post messages

Post messages with embedded img tags were only producing [image]
placeholder text — the actual image_key was discarded and never
downloaded. Now extractPostImageKeys() collects image keys from
post JSON, and resolvePostImages() downloads them via the existing
Lark resource API. Also handles reply-to-post with images.

Refactored: shared resolvePostElements() helper for language variant
lookup, mediaMaxBytes() helper, and dedup via seen map.

internal/channels/feishu/bot.go

@@ -182,6 +182,10 @@ func (c *Channel) handleMessageEvent(ctx context.Context, event *MessageEvent) {
 	switch mc.ContentType {
 	case "image", "file", "audio", "video", "sticker":
 		mediaList = append(mediaList, c.resolveMediaFromMessage(ctx, mc.MessageID, mc.ContentType, msg.Content)...)
+	case "post":
+		if imageKeys := extractPostImageKeys(msg.Content); len(imageKeys) > 0 {
+			mediaList = append(mediaList, c.resolvePostImages(ctx, mc.MessageID, imageKeys)...)
+		}
 	}
 
 	// 11. Process media: STT transcription, document extraction, build tags
@@ -305,19 +309,23 @@ func (c *Channel) fetchReplyContext(ctx context.Context, parentID string) (strin
 		replyCtx = fmt.Sprintf("[Replying to %s]\n%s\n[/Replying]", senderName, body)
 	}
 
-	// Download media from parent message (image, file, audio, video, sticker).
+	// Download media from parent message (image, file, audio, video, sticker, post).
 	var replyMedia []media.MediaInfo
 	switch item.MsgType {
 	case "image", "file", "audio", "video", "sticker":
 		replyMedia = c.resolveMediaFromMessage(ctx, parentID, item.MsgType, item.Body.Content)
-		for i := range replyMedia {
-			replyMedia[i].FromReply = true
-		}
-		if len(replyMedia) > 0 {
-			slog.Debug("feishu: resolved media from replied message",
-				"parent_id", parentID, "media_count", len(replyMedia))
+	case "post":
+		if imageKeys := extractPostImageKeys(item.Body.Content); len(imageKeys) > 0 {
+			replyMedia = c.resolvePostImages(ctx, parentID, imageKeys)
 		}
 	}
+	for i := range replyMedia {
+		replyMedia[i].FromReply = true
+	}
+	if len(replyMedia) > 0 {
+		slog.Debug("feishu: resolved media from replied message",
+			"parent_id", parentID, "media_count", len(replyMedia))
+	}
 
 	return replyCtx, replyMedia
 }

internal/channels/feishu/bot_parse.go

@@ -99,10 +99,12 @@ func parseMessageContent(rawContent, messageType string) string {
 	}
 }
 
-func parsePostContent(rawContent string) string {
+// resolvePostElements extracts the flattened element list from a Lark post message JSON.
+// Handles language variant lookup (zh_cn → en_us → any first key).
+func resolvePostElements(rawContent string) []any {
 	var post map[string]any
 	if err := json.Unmarshal([]byte(rawContent), &post); err != nil {
-		return rawContent
+		return nil
 	}
 
 	var langContent any
@@ -119,16 +121,24 @@ func parsePostContent(rawContent string) string {
 		}
 	}
 	if langContent == nil {
-		return rawContent
+		return nil
 	}
 
 	langMap, ok := langContent.(map[string]any)
 	if !ok {
-		return rawContent
+		return nil
 	}
 
 	contentArr, ok := langMap["content"].([]any)
 	if !ok {
+		return nil
+	}
+	return contentArr
+}
+
+func parsePostContent(rawContent string) string {
+	contentArr := resolvePostElements(rawContent)
+	if contentArr == nil {
 		return rawContent
 	}
 
@@ -179,6 +189,40 @@ func parsePostContent(rawContent string) string {
 	return strings.Join(textParts, "\n")
 }
 
+// extractPostImageKeys parses post content JSON and returns deduplicated image_key
+// values from embedded img tags. Used to download images inline in post messages.
+func extractPostImageKeys(rawContent string) []string {
+	contentArr := resolvePostElements(rawContent)
+	if contentArr == nil {
+		return nil
+	}
+
+	seen := make(map[string]struct{})
+	var keys []string
+	for _, para := range contentArr {
+		paraArr, ok := para.([]any)
+		if !ok {
+			continue
+		}
+		for _, elem := range paraArr {
+			elemMap, ok := elem.(map[string]any)
+			if !ok {
+				continue
+			}
+			tag, _ := elemMap["tag"].(string)
+			if tag == "img" {
+				if key, ok := elemMap["image_key"].(string); ok && key != "" {
+					if _, dup := seen[key]; !dup {
+						seen[key] = struct{}{}
+						keys = append(keys, key)
+					}
+				}
+			}
+		}
+	}
+	return keys
+}
+
 // resolveMentions replaces mention placeholders (@_user_1, @_user_2, etc.) in content.
 // Bot mention is stripped entirely; other user mentions become @Name.
 func resolveMentions(text string, mentions []mentionInfo, botOpenID string) string {

internal/channels/feishu/media_inbound.go

@@ -12,13 +12,19 @@ import (
 	"github.com/nextlevelbuilder/goclaw/internal/channels/media"
 )
 
-// resolveMediaFromMessage extracts and downloads media from a Feishu message.
-// Returns a list of MediaInfo for each media item found.
-func (c *Channel) resolveMediaFromMessage(ctx context.Context, messageID, messageType, rawContent string) []media.MediaInfo {
+// mediaMaxBytes returns the configured per-file size limit in bytes.
+func (c *Channel) mediaMaxBytes() int64 {
 	maxBytes := int64(c.cfg.MediaMaxMB) * 1024 * 1024
 	if maxBytes <= 0 {
 		maxBytes = int64(defaultMediaMaxMB) * 1024 * 1024
 	}
+	return maxBytes
+}
+
+// resolveMediaFromMessage extracts and downloads media from a Feishu message.
+// Returns a list of MediaInfo for each media item found.
+func (c *Channel) resolveMediaFromMessage(ctx context.Context, messageID, messageType, rawContent string) []media.MediaInfo {
+	maxBytes := c.mediaMaxBytes()
 
 	var results []media.MediaInfo
 
@@ -140,6 +146,34 @@ func (c *Channel) resolveMediaFromMessage(ctx context.Context, messageID, messag
 	return results
 }
 
+// resolvePostImages downloads images embedded in post messages by their image_key.
+// Uses continue-on-error so one failed image doesn't skip the rest.
+func (c *Channel) resolvePostImages(ctx context.Context, messageID string, imageKeys []string) []media.MediaInfo {
+	maxBytes := c.mediaMaxBytes()
+
+	var results []media.MediaInfo
+	for _, key := range imageKeys {
+		data, _, err := c.downloadMessageResource(ctx, messageID, key, "image")
+		if err != nil {
+			slog.Debug("feishu download post image failed", "message_id", messageID, "image_key", key, "error", err)
+			continue
+		}
+		if int64(len(data)) > maxBytes {
+			slog.Debug("feishu post image too large", "size", len(data), "max", maxBytes)
+			continue
+		}
+		path, err := saveMediaToTemp(data, "img", ".png")
+		if err != nil {
+			slog.Debug("feishu save post image failed", "error", err)
+			continue
+		}
+		results = append(results, media.MediaInfo{
+			Type: media.TypeImage, FilePath: path, ContentType: "image/png",
+		})
+	}
+	return results
+}
+
 // saveMediaToTemp writes media bytes to a temp file and returns the path.
 func saveMediaToTemp(data []byte, prefix, ext string) (string, error) {
 	if ext == "" {