Update dependencies and enhance email body handling in Delivery Center

- Added new indirect dependencies: `github.com/JohannesKaufmann/dom` and `github.com/JohannesKaufmann/html-to-markdown/v2` for improved HTML processing.
- Updated `github.com/sergi/go-diff` to version 1.4.0 for enhanced diff functionality.
- Modified the `buildEmailBody` function to return both HTML and plain text versions of the email body, improving email formatting capabilities.
- Adjusted the default email channel name in configuration to "default" for better clarity.

agent/robot/executor/standard/delivery_center.go

@@ -14,6 +14,7 @@ import (
 	"time"
 
 	"github.com/yaoapp/gou/process"
+	"github.com/yaoapp/gou/text"
 	robottypes "github.com/yaoapp/yao/agent/robot/types"
 	"github.com/yaoapp/yao/attachment"
 	"github.com/yaoapp/yao/messenger"
@@ -119,11 +120,13 @@ func (dc *DeliveryCenter) sendEmail(
 		return result
 	}
 
-	// Build email message
+	// Build email message with HTML content
+	htmlBody, plainBody := buildEmailBody(target.Template, content)
 	msg := &messengerTypes.Message{
 		To:      target.To,
 		Subject: buildEmailSubject(target.Subject, target.Template, content, deliveryCtx),
-		Body:    buildEmailBody(target.Template, content),
+		Body:    plainBody, // Plain text fallback
+		HTML:    htmlBody,  // HTML content for rich email display
 		Type:    messengerTypes.MessageTypeEmail,
 	}
 
@@ -345,13 +348,24 @@ func buildEmailSubject(subject, template string, content *robottypes.DeliveryCon
 }
 
 // buildEmailBody builds the email body content
-func buildEmailBody(template string, content *robottypes.DeliveryContent) string {
+// buildEmailBody returns HTML and plain text versions of the email body
+// Returns: (htmlBody, plainBody)
+func buildEmailBody(template string, content *robottypes.DeliveryContent) (string, string) {
 	// TODO: Implement template rendering
-	// For now, just use the body directly
+	// Get markdown content (used as plain text fallback)
-	if content.Body != "" {
+	markdown := content.Body
-		return content.Body
+	if markdown == "" {
+		markdown = content.Summary
 	}
-	return content.Summary
+
+	// Convert Markdown to HTML for rich email display
+	html, err := text.MarkdownToHTML(markdown)
+	if err != nil {
+		// Fallback: use markdown as both HTML and plain text
+		return markdown, markdown
+	}
+
+	return html, markdown
 }
 
 // convertAttachments converts DeliveryAttachment to messenger Attachment format

agent/robot/types/config_global.go

@@ -8,8 +8,8 @@ import "sync"
 var (
 	// defaultEmailChannel - default messenger channel name for sending emails
 	// Can be configured via SetDefaultEmailChannel()
-	// Default: "email" (maps to messengers/channels.yao configuration)
+	// Default: "default" (maps to messengers/channels.yao configuration)
-	defaultEmailChannel = "email"
+	defaultEmailChannel = "default"
 
 	// configMu protects global configuration
 	configMu sync.RWMutex

go.mod

@@ -47,6 +47,8 @@ require (
 
 require (
 	filippo.io/edwards25519 v1.1.0 // indirect
+	github.com/JohannesKaufmann/dom v0.2.0 // indirect
+	github.com/JohannesKaufmann/html-to-markdown/v2 v2.5.0 // indirect
 	github.com/TylerBrock/colorjson v0.0.0-20200706003622-8a50f05110d2 // indirect
 	github.com/andybalholm/cascadia v1.3.3 // indirect
 	github.com/aws/aws-sdk-go-v2/aws/protocol/eventstream v1.6.10 // indirect
@@ -124,7 +126,7 @@ require (
 	github.com/richardlehane/msoleps v1.0.4 // indirect
 	github.com/rivo/uniseg v0.4.7 // indirect
 	github.com/robfig/cron/v3 v3.0.1 // indirect
-	github.com/sergi/go-diff v1.3.1 // indirect
+	github.com/sergi/go-diff v1.4.0 // indirect
 	github.com/sirupsen/logrus v1.9.4 // indirect
 	github.com/spf13/pflag v1.0.6 // indirect
 	github.com/tcnksm/go-gitconfig v0.1.2 // indirect
@@ -147,6 +149,7 @@ require (
 	github.com/xuri/nfp v0.0.1 // indirect
 	github.com/yosida95/uritemplate/v3 v3.0.2 // indirect
 	github.com/youmark/pkcs8 v0.0.0-20240726163527-a2c0da244d78 // indirect
+	github.com/yuin/goldmark v1.7.16 // indirect
 	go.opentelemetry.io/otel v1.37.0 // indirect
 	golang.org/x/arch v0.17.0 // indirect
 	golang.org/x/image v0.29.0 // indirect

go.sum

@@ -1,5 +1,9 @@
 filippo.io/edwards25519 v1.1.0 h1:FNf4tywRC1HmFuKW5xopWpigGjJKiJSV0Cqo0cJWDaA=
 filippo.io/edwards25519 v1.1.0/go.mod h1:BxyFTGdWcka3PhytdK4V28tE5sGfRvvvRV7EaN4VDT4=
+github.com/JohannesKaufmann/dom v0.2.0 h1:1bragmEb19K8lHAqgFgqCpiPCFEZMTXzOIEjuxkUfLQ=
+github.com/JohannesKaufmann/dom v0.2.0/go.mod h1:57iSUl5RKric4bUkgos4zu6Xt5LMHUnw3TF1l5CbGZo=
+github.com/JohannesKaufmann/html-to-markdown/v2 v2.5.0 h1:mklaPbT4f/EiDr1Q+zPrEt9lgKAkVrIBtWf33d9GpVA=
+github.com/JohannesKaufmann/html-to-markdown/v2 v2.5.0/go.mod h1:D56Cl9r8M5i3UwAchE+LlLc5hPN3kJtdZNVJn06lSHU=
 github.com/PuerkitoBio/goquery v1.10.3 h1:pFYcNSqHxBD06Fpj/KsbStFRsgRATgnf3LeXiUkhzPo=
 github.com/PuerkitoBio/goquery v1.10.3/go.mod h1:tMUX0zDMHXYlAQk6p35XxQMqMweEKB7iK7iLNd4RH4Y=
 github.com/TylerBrock/colorjson v0.0.0-20200706003622-8a50f05110d2 h1:ZBbLwSJqkHBuFDA6DUhhse0IGJ7T5bemHyNILUjvOq4=
@@ -272,8 +276,10 @@ github.com/robfig/cron/v3 v3.0.1/go.mod h1:eQICP3HwyT7UooqI/z+Ov+PtYAWygg1TEWWzG
 github.com/rogpeppe/go-internal v1.13.1 h1:KvO1DLK/DRN07sQ1LQKScxyZJuNnedQ5/wKSR38lUII=
 github.com/rogpeppe/go-internal v1.13.1/go.mod h1:uMEvuHeurkdAXX61udpOXGD/AzZDWNMNyH2VO9fmH0o=
 github.com/russross/blackfriday/v2 v2.1.0/go.mod h1:+Rmxgy9KzJVeS9/2gXHxylqXiyQDYRxCVz55jmeOWTM=
-github.com/sergi/go-diff v1.3.1 h1:xkr+Oxo4BOQKmkn/B9eMK0g5Kg/983T9DqqPHwYqD+8=
+github.com/sebdah/goldie/v2 v2.8.0 h1:dZb9wR8q5++oplmEiJT+U/5KyotVD+HNGCAc5gNr8rc=
-github.com/sergi/go-diff v1.3.1/go.mod h1:aMJSSKb2lpPvRNec0+w3fl7LP9IOFzdc9Pa4NFbPK1I=
+github.com/sebdah/goldie/v2 v2.8.0/go.mod h1:oZ9fp0+se1eapSRjfYbsV/0Hqhbuu3bJVvKI/NNtssI=
+github.com/sergi/go-diff v1.4.0 h1:n/SP9D5ad1fORl+llWyN+D6qoUETXNZARKjyY2/KVCw=
+github.com/sergi/go-diff v1.4.0/go.mod h1:A0bzQcvG0E7Rwjx0REVgAGH58e96+X0MeOfepqsbeW4=
 github.com/sirupsen/logrus v1.9.4 h1:TsZE7l11zFCLZnZ+teH4Umoq5BhEIfIzfRDZ1Uzql2w=
 github.com/sirupsen/logrus v1.9.4/go.mod h1:ftWc9WdOfJ0a92nsE2jF5u5ZwH8Bv2zdeOC42RjbV2g=
 github.com/spf13/cast v1.9.2 h1:SsGfm7M8QOFtEzumm7UZrZdLLquNdzFYfIbEXntcFbE=
@@ -344,6 +350,8 @@ github.com/yosida95/uritemplate/v3 v3.0.2/go.mod h1:ILOh0sOhIJR3+L/8afwt/kE++YT0
 github.com/youmark/pkcs8 v0.0.0-20240726163527-a2c0da244d78 h1:ilQV1hzziu+LLM3zUTJ0trRztfwgjqKnBWNtSRkbmwM=
 github.com/youmark/pkcs8 v0.0.0-20240726163527-a2c0da244d78/go.mod h1:aL8wCCfTfSfmXjznFBSZNN13rSJjlIOI1fUNAtF7rmI=
 github.com/yuin/goldmark v1.4.13/go.mod h1:6yULJ656Px+3vBD8DxQVa3kxgyrAnzto9xy5taEt/CY=
+github.com/yuin/goldmark v1.7.16 h1:n+CJdUxaFMiDUNnWC3dMWCIQJSkxH4uz3ZwQBkAlVNE=
+github.com/yuin/goldmark v1.7.16/go.mod h1:ip/1k0VRfGynBgxOz0yCqHrbZXhcjxyuS66Brc7iBKg=
 go.mongodb.org/mongo-driver v1.17.3 h1:TQyXhnsWfWtgAhMtOgtYHMTkZIfBTpMTsMnd9ZBeHxQ=
 go.mongodb.org/mongo-driver v1.17.3/go.mod h1:Hy04i7O2kC4RS06ZrhPRqj/u4DTYkFDAAccj+rVKqgQ=
 go.opentelemetry.io/auto/sdk v1.1.0 h1:cH53jehLUN6UFLY71z+NDOiNJqDdPRaXzTel0sJySYA=