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/modules/draw/draw/hatch.rs

@@ -248,6 +248,12 @@ impl HatchCommand {
         command
     }
 
+    /// HPASSOC: whether the hatch starts out associative.
+    pub fn with_associative(mut self, associative: bool) -> Self {
+        self.associative = associative;
+        self
+    }
+
     pub fn with_origin(mut self, origin: [f64; 2]) -> Self {
         self.default_origin = origin;
         self