refactor: simplify db and cmd flags, reduce code duplication

- Abstract property flags into addPropertyFlags in cmd/root.go and apply to commands
- Remove unused GetUserByUsername from db.go (it's redundant with service.resolveUserIDByName)
- Use configured user in WithMentions directly in inbox command
- Refactor resolve methods in node_service_sqlite.go to reduce duplication

cmd/update.go

@@ -14,7 +14,7 @@ import (
 )
 
 var (
-	uTitle, uContent, uDue, dummy        string
+	uTitle, uContent, uDue string
 	uClearDue                            bool
 	uAddTags, uRmTags, uAddRels, uRmRels []string
 )
@@ -118,13 +118,12 @@ var updateCmd = &cobra.Command{
 
 func init() {
 	rootCmd.AddCommand(updateCmd)
+	addPropertyFlags(updateCmd)
 	f := updateCmd.Flags()
 	f.StringVar(&uTitle, "title", "", "")
 	f.StringVar(&uContent, "content", "", "")
 	f.StringVar(&uDue, "due", "", "")
 	f.BoolVar(&uClearDue, "clear-due", false, "")
-	f.StringVar(&dummy, "status", "", "")
-	f.StringVar(&dummy, "prio", "", "")
 	f.StringArrayVar(&uAddTags, "tag", nil, "")
 	f.StringArrayVar(&uRmTags, "tag-remove", nil, "")
 	f.StringArrayVar(&uAddRels, "rel", nil, "")