Support aligned dimension associations

src/command.rs

@@ -1212,10 +1212,12 @@ pub enum CmdResult {
     CommitEntitiesAndExit(Vec<EntityType>),
     /// Commit an acadrust entity to the document and end the command.
     CommitAndExit(EntityType),
-    /// Commit an object-selected linear dimension and retain its source link.
-    CommitAssociativeDimension {
+    /// Commit a linear/aligned dimension while honoring the drawing's
+    /// association mode. `source` is present for object-selection workflows;
+    /// point-created dimensions resolve sources from their snapped endpoints.
+    CommitDimension {
         entity: EntityType,
-        source: Handle,
+        source: Option<Handle>,
     },
     /// Commit a Model-tab 3D solid: the acadrust entity (for selection /
     /// persistence) plus its B-rep (cached for boolean ops + shaded