fix(channel,attachment): channel quality refactor & attachment pipeline fixes (#349)

* feat(channel): add DingTalk channel adapter

- Add DingTalk channel adapter (`internal/channel/adapters/dingtalk/`) using dingtalk-stream-sdk-go, supporting inbound message receiving and outbound text/markdown reply
- Register DingTalk adapter in cmd/agent and cmd/memoh
- Add go.mod dependency: github.com/memohai/dingtalk-stream-sdk-go
- Add Dingtalk and Wecom SVG icons and Vue components to @memohai/icon
- Refactor existing icon components to remove redundant inline wrappers
- Add `channelTypeDisplayName` util for consistent channel label resolution
- Add DingTalk/WeCom i18n entries (en/zh) for types and typesShort
- Extend channel-icon, bot-channels, channel-settings-panel to support dingtalk/wecom
- Use channelTypeDisplayName in profile page to replace ad-hoc i18n lookup

* fix(channel,attachment): channel quality refactor & attachment pipeline fixes

Channel module:
- Fix RemoveAdapter not cleaning connectionMeta (stale status leak)
- Fix preparedAttachmentTypeFromMime misclassifying image/gif
- Fix sleepWithContext time.After goroutine/timer leak
- Export IsDataURL/IsHTTPURL/IsDataPath, dedup across packages
- Cache OutboundPolicy in managerOutboundStream to avoid repeated lookups
- Split OutboundAttachmentStore: extract ContainerAttachmentIngester interface
- Add ManagerOption funcs (WithInboundQueueSize, WithInboundWorkers, WithRefreshInterval)
- Add thread-safety docs on OutboundStream / managerOutboundStream
- Add debug logs on successful send/edit paths
- Expand outbound_prepare_test.go with 21 new cases
- Convert no-receiver adapter helpers to package-level funcs; drop unused params

DingTalk adapter:
- Implement AttachmentResolver: download inbound media via /v1.0/robot/messageFiles/download
- Fix pure-image inbound messages failing due to missing resolver

Attachment pipeline:
- Fix images invisible to LLM in pipeline (DCP) path: inject InlineImages into
  last user message when cfg.Query is empty
- Fix public_url fallback: skip direct URL-to-LLM when ContentHash is set,
  always prefer inlined persisted asset
- Inject path: carry ImageParts through agent.InjectMessage; inline persisted
  attachments in resolver inject goroutine so mid-stream images reach the model
- Fix ResolveMime for images: prefer content-sniffed MIME over platform-declared
  MIME (fixes Feishu sending image/png header for actual JPEG content → API 400)

internal/conversation/flow/resolver.go

@@ -257,10 +257,16 @@ func (r *Resolver) resolve(ctx context.Context, req conversation.ChatRequest) (r
 		agentInjectCh := make(chan agentpkg.InjectMessage, cap(req.InjectCh))
 		go func() {
 			for msg := range req.InjectCh {
-				agentInjectCh <- agentpkg.InjectMessage{
+				agentMsg := agentpkg.InjectMessage{
 					Text:            msg.Text,
 					HeaderifiedText: msg.HeaderifiedText,
 				}
+				// Inline any image attachments from the injected message so the
+				// model receives them as vision input alongside the text.
+				if runCfg.SupportsImageInput && len(msg.Attachments) > 0 {
+					agentMsg.ImageParts = r.inlineInjectAttachments(ctx, req.BotID, msg.Attachments)
+				}
+				agentInjectCh <- agentMsg
 			}
 			close(agentInjectCh)
 		}()
@@ -500,6 +506,29 @@ func (r *Resolver) prepareRunConfig(ctx context.Context, cfg agentpkg.RunConfig)
 			}
 		}
 		cfg.Messages = append(cfg.Messages, sdk.UserMessage(cfg.Query, extra...))
+	} else if len(cfg.InlineImages) > 0 {
+		// Pipeline path: the user query is already embedded in the RC messages,
+		// but image parts are not rendered by the pipeline renderer. Inject the
+		// inline images into the last user message so the model receives them.
+		imageParts := make([]sdk.MessagePart, 0, len(cfg.InlineImages))
+		for _, img := range cfg.InlineImages {
+			if strings.TrimSpace(img.Image) != "" {
+				imageParts = append(imageParts, img)
+			}
+		}
+		if len(imageParts) > 0 {
+			injected := false
+			for i := len(cfg.Messages) - 1; i >= 0; i-- {
+				if cfg.Messages[i].Role == sdk.MessageRoleUser {
+					cfg.Messages[i].Content = append(cfg.Messages[i].Content, imageParts...)
+					injected = true
+					break
+				}
+			}
+			if !injected {
+				cfg.Messages = append(cfg.Messages, sdk.UserMessage("", imageParts...))
+			}
+		}
 	}
 
 	return cfg