fix(share): add more social media bot user agents

Add facebookcatalog, meta-externalagent, pinterestbot and organize
bot list with comments by platform.

pkg/util/user_agent.go

@@ -5,14 +5,25 @@ import "strings"
 // IsSocialMediaBot checks if the User-Agent belongs to a social media crawler.
 func IsSocialMediaBot(ua string) bool {
 	bots := []string{
+		// Meta (Facebook, Instagram, WhatsApp)
 		"facebookexternalhit",
+		"facebookcatalog",
+		"facebot",
+		"meta-externalagent",
+		// Twitter/X
 		"twitterbot",
+		// LinkedIn
 		"linkedinbot",
-		"whatsapp",
-		"slackbot",
+		// Discord
 		"discordbot",
+		// Telegram
 		"telegrambot",
-		"facebot",
+		// Slack
+		"slackbot",
+		// WhatsApp
+		"whatsapp",
+		// Pinterest
+		"pinterestbot",
 	}
 	ua = strings.ToLower(ua)
 	for _, bot := range bots {