fix(clipboard): carry block-internal layers and refresh the layer panel

Cross-drawing paste recreated layers/linetypes/styles only for the
top-level selection, so objects inside a pasted block landed on layers the
target drawing didn't have. Scan the entities inside captured block
definitions for their dependencies too. Also refresh the layer panel after
a paste so the brought-in layers show in the manager and the dropdown.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

src/app/cmd_result.rs

@@ -623,6 +623,9 @@ impl OpenCADStudio {
                     // render instead of staying invisible. (#135)
                     self.tabs[i].scene.populate_meshes_from_document();
                     self.tabs[i].dirty = true;
+                    // Surface any layers the paste brought in (cross-drawing)
+                    // in the layer manager and the layer dropdown.
+                    self.refresh_layer_panel();
                     self.refresh_properties();
                     self.command_line
                         .push_info(&format!("{count} object(s) pasted."));

src/app/mod.rs

@@ -684,7 +684,12 @@ impl ClipboardDeps {
                 || n.eq_ignore_ascii_case("ByLayer")
                 || n.eq_ignore_ascii_case("ByBlock")
         };
-        for e in entities {
+        // Scan the copied entities AND the entities inside every captured
+        // block definition, so a block-internal object's layer / linetype /
+        // style is recreated too — not just the top-level selection's.
+        let blocks = Self::capture_blocks(doc, entities);
+        let block_entities = blocks.iter().flat_map(|d| d.entities.iter());
+        for e in entities.iter().chain(block_entities) {
             let c = e.common();
             if !c.layer.is_empty() {
                 layers.insert(c.layer.clone());
@@ -719,7 +724,7 @@ impl ClipboardDeps {
             linetypes: ltypes.iter().filter_map(|n| doc.line_types.get(n).cloned()).collect(),
             text_styles: tstyles.iter().filter_map(|n| doc.text_styles.get(n).cloned()).collect(),
             dim_styles: dstyles.iter().filter_map(|n| doc.dim_styles.get(n).cloned()).collect(),
-            blocks: Self::capture_blocks(doc, entities),
+            blocks,
         }
     }