feat(parse): report per-sheet recognition and block error sheets

- parseWorkbook returns a report per sheet (table counts, issues, ok)
- sheets with E-level issues cannot be selected (spec section 2.3)
- pier input carries its source sheet name

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

tests/p1-regression.test.ts

@@ -100,3 +100,9 @@ describe('P1 regression — spec.md §12', () => {
     expect(f.top - f.bottom).toBeCloseTo(2.0, 4);
   });
 });
+
+describe('pile layout text (spec §12, §6.8 display)', () => {
+  it('reads 4@2250 × 3@2250 = 20본', () => {
+    expect(model.derived.pileLayout).toBe('4@2250 × 3@2250 = 20본');
+  });
+});