feat(hatch): HPASSOC sets whether new hatches are associative

HPASSOC (0 or 1, default 1) is the starting state of the hatch
command's associative option. It is an application setting: typed
directly or through SETVAR, it persists across sessions and does not
mark the drawing modified.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

src/app/commands/draw.rs

@@ -764,7 +764,8 @@ impl OpenCADStudio {
                 });
                 let new_cmd =
                     HatchCommand::new(outlines, boundary_sources, selected, inherited, plane)
-                        .with_origin(self.tabs[i].scene.document.hatch_origin());
+                        .with_origin(self.tabs[i].scene.document.hatch_origin())
+                        .with_associative(self.hatch_associative);
                 self.command_line.push_info(&new_cmd.prompt());
                 self.tabs[i].active_cmd = Some(Box::new(new_cmd));
                 self.refresh_area_preview(i);

src/app/commands/styleprops.rs

@@ -1148,6 +1148,7 @@ impl OpenCADStudio {
                     | "SHORTCUTMENUDURATION"
                     | "CURSORSIZE"
                     | "PICKBOX"
+                    | "HPASSOC"
                     | "CURSORTYPE"
                     | "SNAPANG"
                     | "TEXTFILL"
@@ -2188,6 +2189,17 @@ impl OpenCADStudio {
                                 },
                                 None => Ok((format!("PICKBOX = {}", self.pick_box), false)),
                             },
+                            "HPASSOC" => match value.as_deref() {
+                                Some(v @ ("0" | "1")) => {
+                                    self.hatch_associative = v == "1";
+                                    Ok((format!("HPASSOC = {v}"), true))
+                                }
+                                Some(_) => Err("SETVAR: 0 or 1 required.".into()),
+                                None => Ok((
+                                    format!("HPASSOC = {}", u8::from(self.hatch_associative)),
+                                    false,
+                                )),
+                            },
                             "CURSORTYPE" => match &value {
                                 Some(v) => match v.as_str() {
                                     "0" => {
@@ -3134,6 +3146,7 @@ impl OpenCADStudio {
                                         | "SHORTCUTMENUDURATION"
                                         | "CURSORSIZE"
                                         | "PICKBOX"
+                                        | "HPASSOC"
                                         | "CURSORTYPE"
                                         | "SNAPANG"
                                         | "CLIPROMPTLINES"