fix: preserve meeting note file metadata

internal/httpapi/payload.go

@@ -2,6 +2,8 @@ package httpapi
 
 import (
 	"encoding/json"
+	"mime"
+	"path/filepath"
 	"strings"
 	"time"
 
@@ -315,13 +317,18 @@ func meetingNotesDetailPayload(meeting store.Meeting, files []store.MeetingNoteF
 }
 
 func meetingNoteFilePayload(file store.MeetingNoteFile, viewer int64) map[string]any {
+	extension := meetingNoteFileExtension(file.FileName, file.MIMEType)
 	return map[string]any{
 		"note_file_id":     file.NoteFileID,
 		"meeting_id":       file.MeetingID,
 		"file_id":          file.FileID,
+		"name":             file.FileName,
 		"file_name":        file.FileName,
+		"mime":             file.MIMEType,
 		"mime_type":        file.MIMEType,
+		"size":             file.FileSize,
 		"file_size":        file.FileSize,
+		"file_extension":   extension,
 		"file_etag":        file.FileETag,
 		"status":           file.Status,
 		"preview_status":   file.PreviewStatus,
@@ -341,6 +348,17 @@ func meetingNoteFilePayload(file store.MeetingNoteFile, viewer int64) map[string
 	}
 }
 
+func meetingNoteFileExtension(fileName, mimeType string) string {
+	if ext := strings.ToLower(strings.TrimPrefix(filepath.Ext(strings.TrimSpace(fileName)), ".")); ext != "" {
+		return ext
+	}
+	exts, _ := mime.ExtensionsByType(strings.TrimSpace(mimeType))
+	if len(exts) == 0 {
+		return ""
+	}
+	return strings.ToLower(strings.TrimPrefix(exts[0], "."))
+}
+
 func dailyReportPayloads(reports []store.DailyReport) []map[string]any {
 	items := make([]map[string]any, 0, len(reports))
 	for _, report := range reports {