🐛 fix(snippet): 保留代码片段尾部空白

- 持久化时完整保留代码片段正文中的尾部空格与换行
- 继续拒绝仅包含空白字符的无效片段
- 补充保存、存储及重新加载后的正文一致性测试

frontend/src/store.test.ts

@@ -2268,4 +2268,29 @@ describe('store appearance persistence', () => {
     expect(persistedSnippets).toHaveLength(1);
     expect(persistedSnippets[0].syntaxHelp).toBe('新说明：目标表、数据源、关联字段均可修改');
   });
+
+  it('preserves custom SQL snippet body whitespace across reloads', async () => {
+    const { useStore } = await importStore();
+    const body = 'SELECT ${1:columns} FROM ${2:table_name}\n  ';
+
+    useStore.getState().saveSqlSnippet({
+      id: 'custom-trailing-whitespace',
+      prefix: 'trail',
+      name: 'Trailing whitespace',
+      body,
+      isBuiltin: false,
+      createdAt: 1710000000000,
+    });
+
+    expect(useStore.getState().sqlSnippets.find((snippet) => snippet.id === 'custom-trailing-whitespace')?.body)
+      .toBe(body);
+    const persisted = JSON.parse(storage.getItem('lite-db-storage') || '{}');
+    expect(persisted.state.sqlSnippets.find((snippet: { id: string }) => snippet.id === 'custom-trailing-whitespace')?.body)
+      .toBe(body);
+
+    vi.resetModules();
+    const reloaded = await importStore();
+    expect(reloaded.useStore.getState().sqlSnippets.find((snippet) => snippet.id === 'custom-trailing-whitespace')?.body)
+      .toBe(body);
+  });
 });

frontend/src/store.ts

@@ -1664,8 +1664,8 @@ const sanitizeSqlSnippets = (value: unknown): SqlSnippet[] => {
       .toLowerCase()
       .replace(/[^a-z0-9_]/g, "")
       .slice(0, 20);
-    const body = toTrimmedString(raw.body);
-    if (!prefix || !body) return;
+    const body = typeof raw.body === "string" ? raw.body : "";
+    if (!prefix || !body.trim()) return;
     const id = toTrimmedString(raw.id, `snippet-${index + 1}`) || `snippet-${index + 1}`;
     const fallbackName = indexedStoreFallback(
       "store.fallback.sql_snippet_name",