fix(media): set result.Media on create_image and add MEDIA: fallback in subagent exec

Root cause: create_image tool only set ForLLM:"MEDIA:path" but never
populated result.Media. The main agent loop parses MEDIA: prefix via
parseMediaResult(), but the subagent exec loop only checked result.Media
— so media paths were silently lost for all subagent/spawn workflows.

This caused the entire downstream pipeline (task.Media → AnnounceQueue →
PublishInbound → ContentSuffix → session) to receive empty media, making
images invisible in WS chat despite Telegram working fine.

Fixes:
- create_image.go: set result.Media = []string{imagePath}
- subagent_exec.go: add MEDIA: prefix fallback parsing as safety net

internal/tools/create_image.go

@@ -131,6 +131,7 @@ func (t *CreateImageTool) Execute(ctx context.Context, args map[string]interface
 	}
 
 	result := &Result{ForLLM: fmt.Sprintf("MEDIA:%s", imagePath)}
+	result.Media = []string{imagePath}
 	result.Deliverable = fmt.Sprintf("[Generated image: %s]\nPrompt: %s", filepath.Base(imagePath), prompt)
 	result.Provider = providerName
 	result.Model = model

internal/tools/subagent_exec.go

@@ -5,6 +5,7 @@ import (
 	"encoding/json"
 	"fmt"
 	"log/slog"
+	"strings"
 	"time"
 
 	"github.com/nextlevelbuilder/goclaw/internal/bus"
@@ -229,6 +230,15 @@ func (sm *SubagentManager) executeTask(ctx context.Context, task *SubagentTask)
 			// Capture media file paths from tool results (e.g. image generation).
 			if len(result.Media) > 0 {
 				mediaPaths = append(mediaPaths, result.Media...)
+			} else if strings.HasPrefix(strings.TrimSpace(result.ForLLM), "MEDIA:") {
+				// Fallback: parse MEDIA: prefix from ForLLM (same as agent loop's parseMediaResult)
+				p := strings.TrimSpace(strings.TrimSpace(result.ForLLM)[6:])
+				if nl := strings.IndexByte(p, '\n'); nl >= 0 {
+					p = strings.TrimSpace(p[:nl])
+				}
+				if p != "" {
+					mediaPaths = append(mediaPaths, p)
+				}
 			}
 
 			messages = append(messages, providers.Message{