Co-locate CadCommand impls with their ribbon toolbar modules

Each command implementation is now in the same file as its ribbon
tool definition. Groups moved to a dedicated groups/ toolbar folder.

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

src/modules/home/layers/match_layer.rs

@@ -1,3 +1,5 @@
+// Match Layer tool — ribbon definition + CadCommand implementation.
+
 use crate::modules::{IconKind, ModuleEvent, ToolDef};
 
 pub fn tool() -> ToolDef {
@@ -8,3 +10,70 @@ pub fn tool() -> ToolDef {
         event: ModuleEvent::Command("LAYMATCH".to_string()),
     }
 }
+
+// ── CadCommand implementation ─────────────────────────────────────────────
+
+use acadrust::Handle;
+use glam::Vec3;
+
+use crate::command::{CadCommand, CmdResult};
+use crate::scene::wire_model::WireModel;
+
+pub struct LayMatchCommand {
+    dest_handles: Vec<Handle>,
+}
+
+impl LayMatchCommand {
+    pub fn new(dest: Vec<Handle>) -> Self {
+        Self { dest_handles: dest }
+    }
+}
+
+impl CadCommand for LayMatchCommand {
+    fn name(&self) -> &'static str {
+        "LAYMATCH"
+    }
+
+    fn prompt(&self) -> String {
+        if self.dest_handles.is_empty() {
+            "LAYMATCH  Select objects to change layer:".into()
+        } else {
+            "LAYMATCH  Select source object to match layer from:".into()
+        }
+    }
+
+    fn is_selection_gathering(&self) -> bool {
+        true
+    }
+
+    fn on_selection_complete(&mut self, handles: Vec<Handle>) -> CmdResult {
+        if handles.is_empty() {
+            return CmdResult::NeedPoint;
+        }
+        if self.dest_handles.is_empty() {
+            // Phase 1 complete — store destinations, move to phase 2.
+            self.dest_handles = handles;
+            CmdResult::NeedPoint
+        } else {
+            // Phase 2 complete — first handle is the source object.
+            let src = handles[0];
+            CmdResult::MatchEntityLayer {
+                dest: std::mem::take(&mut self.dest_handles),
+                src,
+            }
+        }
+    }
+
+    fn on_point(&mut self, _pt: Vec3) -> CmdResult {
+        CmdResult::NeedPoint
+    }
+    fn on_enter(&mut self) -> CmdResult {
+        CmdResult::Cancel
+    }
+    fn on_escape(&mut self) -> CmdResult {
+        CmdResult::Cancel
+    }
+    fn on_hover_entity(&mut self, _handle: Handle, _pt: Vec3) -> Vec<WireModel> {
+        vec![]
+    }
+}