feat(PROJ-26,PROJ-38): IMAP LDAP-Auth + Mail-Threading

pkg/mailparser/parser.go

@@ -28,6 +28,8 @@ type ParsedMail struct {
 	CC          []string
 	Subject     string
 	MessageID   string
+	InReplyTo   string   // In-Reply-To header (single message-id, no angle brackets)
+	References  []string // References header (list of message-ids, no angle brackets)
 	TextBody    string
 	HTMLBody    string
 	Date        time.Time
@@ -81,6 +83,21 @@ func Parse(raw []byte) (*ParsedMail, error) {
 	msgID := msg.Header.Get("Message-Id")
 	pm.MessageID = strings.Trim(msgID, "<>")
 
+	// In-Reply-To - strip angle brackets
+	if irt := msg.Header.Get("In-Reply-To"); irt != "" {
+		pm.InReplyTo = strings.Trim(strings.TrimSpace(irt), "<>")
+	}
+
+	// References - space-separated list of message-ids
+	if refs := msg.Header.Get("References"); refs != "" {
+		for _, r := range strings.Fields(refs) {
+			r = strings.Trim(r, "<>")
+			if r != "" {
+				pm.References = append(pm.References, r)
+			}
+		}
+	}
+
 	// Date — try go-message parser first, then fallback formats, then zero
 	if d, err := msg.Header.Date(); err == nil {
 		pm.Date = d