feat: ATTEDIT — edit block attribute values interactively

- attedit.rs: AtteditCommand picks an INSERT entity then iterates through
  each attribute tag prompting for a new value (Enter keeps existing)
- attedit_pending_handle() / attedit_set_attrs() trait methods inject
  attribute data into the command after entity-pick (avoids document access
  in the command itself)
- cmd_result.rs: NeedPoint handler injects attr data; ReplaceEntity detects
  the __ATTEDIT__ sentinel and calls apply_attedit() on the document
- apply_attedit() encodes tag/value pairs as __ATTEDIT__tag\x01val\x02...
- ROADMAP.md: ATTEDIT marked ✅

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/app/commands.rs

@@ -1442,6 +1442,13 @@ impl H7CAD {
                 self.tabs[i].active_cmd = Some(Box::new(cmd_obj));
             }
 
+            "ATTEDIT"|"ATE"|"-ATTEDIT" => {
+                use crate::modules::home::modify::attedit::AtteditCommand;
+                let cmd_obj = AtteditCommand::new();
+                self.command_line.push_info(&cmd_obj.prompt());
+                self.tabs[i].active_cmd = Some(Box::new(cmd_obj));
+            }
+
             "ALIGN"|"AL" => {
                 use crate::modules::home::modify::align::AlignCommand;
                 let cmd = AlignCommand::new();