fix(rebar): S1 layout dimensions on the outer side of each block in the plan

- The front block's S1 layout goes on the left and the back block's on the right,
  so the text no longer falls into the gap between the two blocks.

Co-Authored-By: Claude Haiku 5.5 <noreply@anthropic.com>

tests/block-rebar-plan-svg.test.ts

@@ -40,3 +40,10 @@ describe('받침블럭 배근 평면 치수 (승인 2026-10-26)', () => {
     expect(svg).toContain('@125=2250');
   });
 });
+
+describe('받침블럭 배근 평면 · S1 치수 위치 (승인 2026-10-26)', () => {
+  it('each S1 layout is written once, on the outer side of its block (front left, back right)', () => {
+    const svg = blockRebarPlanSvg(buildPier(loadP1()), 0);
+    expect(svg.split('7@125=875').length - 1).toBe(4); // S2 and S1 for each of the two blocks
+  });
+});