feat(agent): wire media refs through agent pipeline to LLM provider

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

pkg/agent/context.go

@@ -466,10 +466,14 @@ func (cb *ContextBuilder) BuildMessages(
 
 	// Add current user message
 	if strings.TrimSpace(currentMessage) != "" {
-		messages = append(messages, providers.Message{
+		msg := providers.Message{
 			Role:    "user",
 			Content: currentMessage,
-		})
+		}
+		if len(media) > 0 {
+			msg.Media = media
+		}
+		messages = append(messages, msg)
 	}
 
 	return messages

pkg/agent/loop.go

@@ -51,6 +51,7 @@ type processOptions struct {
 	Channel         string   // Target channel for tool execution
 	ChatID          string   // Target chat ID for tool execution
 	UserMessage     string   // User message content (may include prefix)
+	Media           []string // media:// refs from inbound message
 	DefaultResponse string   // Response when LLM returns empty
 	EnableSummary   bool     // Whether to trigger summarization
 	SendResponse    bool     // Whether to send response via bus
@@ -497,6 +498,7 @@ func (al *AgentLoop) processMessage(ctx context.Context, msg bus.InboundMessage)
 		Channel:         msg.Channel,
 		ChatID:          msg.ChatID,
 		UserMessage:     msg.Content,
+		Media:           msg.Media,
 		DefaultResponse: defaultResponse,
 		EnableSummary:   true,
 		SendResponse:    false,
@@ -603,11 +605,15 @@ func (al *AgentLoop) runAgentLoop(
 		history,
 		summary,
 		opts.UserMessage,
-		nil,
+		opts.Media,
 		opts.Channel,
 		opts.ChatID,
 	)
 
+	// Resolve media:// refs to base64 data URLs (streaming)
+	maxMediaSize := al.cfg.Agents.Defaults.GetMaxMediaSize()
+	messages = resolveMediaRefs(messages, al.mediaStore, maxMediaSize)
+
 	// 3. Save user message to session
 	agent.Sessions.AddMessage(opts.SessionKey, "user", opts.UserMessage)