feat(rebar): add 3D coupler modeling for P1/P2 (368) and P4/P5 (35) with separate summary table rows

tests/rebar3d.test.ts

@@ -67,6 +67,11 @@ describe('3D 철근 모델 (③)', () => {
     expect(rb.byName.get('P6')!.length).toBe(8 * 4 * 3);
   });
 
+  it('couplers in 3D: main bar couplers (368) and tie couplers (35: P5 19 + P4 16)', () => {
+    expect(rb.byName.get('주철근 커플러')!.length).toBe(368);
+    expect(rb.byName.get('띠철근 커플러')!.length).toBe(35);
+  });
+
   it('highlight dims the other bars and keeps the chosen one', () => {
     rb.highlight('P3');
     const p3 = (rb.byName.get('P3')![0].material as THREE.MeshStandardMaterial).opacity;