feat(ground): pile-tip embedment check and soil layers from the ground model

- ground.ts: G04 when a pile tip is above the 연암 상면 minus 1.0 × D; G05
  (info) when layers are entered but there is no 연암 row. No message while
  no layers are entered at all.
- ground-model.ts: reads the Python soil.layers as strata rows; the project
  file keeps and checks them.
- ② card: a button fills the layer rows from the ground model for the pier.

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

tests/ground-inputs.test.ts

@@ -1,6 +1,6 @@
 import { describe, expect, it } from 'vitest';
 import { buildPier } from '../src/core/geometry';
-import { validateGround } from '../src/core/ground';
+import { validateGround, validatePileEmbedment } from '../src/core/ground';
 import { changedKeys } from '../src/core/changes';
 import { COPY_ITEMS, applyCopy, planCopy } from '../src/core/copy';
 import type { Issue, PierInput } from '../src/core/types';
@@ -103,3 +103,35 @@ describe('단면 그림 (삽도)', () => {
     expect(svg).toContain('지반고 28.931');
   });
 });
+
+describe('말뚝 선단 근입 (G04·G05)', () => {
+  // P1 model: pile tips at about EL 2.2 m, D 0.6096 m, so the limit is the 연암 top minus 0.6096.
+  const model = buildPier(base);
+  const deepest = Math.max(...model.piles.map((p) => p.bottom));
+
+  function embed(input: PierInput): string[] {
+    const issues: Issue[] = [];
+    validatePileEmbedment(input, model, issues);
+    return issues.map((i) => i.code);
+  }
+
+  it('no check and no message when no layers are entered yet', () => {
+    expect(embed(withGround({}))).toEqual([]);
+  });
+
+  it('G04: a pile tip above the 연암 top minus the embedment', () => {
+    // 연암 top = the 매립토 bottom 2.5 m, so the limit is 2.5 − 0.6096 = 1.89 m, above the tips at 2.2 m.
+    expect(deepest).toBeGreaterThan(2.5 - 0.6096);
+    const rows = [{ name: '매립토', bottomEl: 2.5 }, { name: '연암', bottomEl: 1 }];
+    expect(embed(withGround({ strataRows: rows }))).toEqual(['G04']);
+  });
+
+  it('no G04 when the 연암 top is high enough above the tips', () => {
+    const rows = [{ name: '매립토', bottomEl: 20 }, { name: '연암', bottomEl: 10 }];
+    expect(embed(withGround({ strataRows: rows }))).toEqual([]);
+  });
+
+  it('G05 (info): layers entered but no 연암 row, so the embedment is not checked', () => {
+    expect(embed(withGround({ strataRows: [{ name: '풍화토', bottomEl: 20 }] }))).toEqual(['G05']);
+  });
+});