fix: hide block definition entities from viewport

Block-definition geometry (entities stored inside named blocks) was
leaking into the viewport when DXF files omit the owner-handle group
code (330) on block-content entities.

The fix tightens `belongs_to_visible_block`: when `owner_handle` is
null, the current layout block-record's `entity_handles` list is used
as the authoritative allow-list before falling back to the older
"not-in-any-other-block" heuristic.  This ensures block definitions
are never rendered directly, only when referenced via an INSERT.

Bumps version to 0.1.4.

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

Cargo.lock

@@ -4,7 +4,7 @@ version = 4
 
 [[package]]
 name = "H7CAD"
-version = "0.1.3"
+version = "0.1.4"
 dependencies = [
  "acadrust",
  "bytemuck",

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "H7CAD"
-version = "0.1.3"
+version = "0.1.4"
 edition = "2021"
 build = "build.rs"
 

src/scene/mod.rs

@@ -429,11 +429,6 @@ impl Scene {
     }
 
     /// Decide whether an entity should be drawn as direct content of `block_handle`.
-    ///
-    /// Normal case: entity.owner_handle equals the active layout/model block.
-    /// Fallback: if owner is null, allow it only when the handle is not listed
-    /// under any other block record. This prevents block-definition geometry
-    /// from leaking into the viewport when malformed files omit owner handles.
     fn belongs_to_visible_block(
         &self,
         entity_handle: Handle,
@@ -450,6 +445,17 @@ impl Scene {
             return false;
         }
 
+        // owner_handle is null (common in DXF files that omit group code 330).
+        // Use the current layout's entity_handles as the authoritative list when
+        // available — this prevents block-definition geometry from leaking into
+        // the viewport even when owner handles are missing.
+        if let Some(br) = self.document.block_records.iter().find(|br| br.handle == block_handle) {
+            if !br.entity_handles.is_empty() {
+                return br.entity_handles.contains(&entity_handle);
+            }
+        }
+
+        // entity_handles not populated: fall back to "not listed in any other block".
         !self
             .document
             .block_records