✨ feat(qdrant): 新增 Qdrant 向量库连接支持

- 后端新增 Qdrant REST 连接、collection 元数据、scroll/search 查询与 upsert/delete/payload 更新

- 前端新增 Qdrant 类型、连接配置、图标、方言和能力矩阵

- 测试覆盖 mock REST、真实服务 smoke 和前端配置

Refs #555

frontend/src/components/DatabaseIcons.test.tsx

@@ -25,6 +25,13 @@ describe('DatabaseIcons', () => {
     expect(markup).toContain('>Ch</text>');
   });
 
+  it('includes Qdrant in the selectable database icons', () => {
+    expect(DB_ICON_TYPES).toContain('qdrant');
+    expect(getDbIconLabel('qdrant')).toBe('Qdrant');
+    const markup = renderToStaticMarkup(<>{getDbIcon('qdrant', undefined, 22)}</>);
+    expect(markup).toContain('>Qd</text>');
+  });
+
   it('wraps database icons in a consistent frame for sidebar sizing', () => {
     const mysqlMarkup = renderToStaticMarkup(<>{getDbIcon('mysql', undefined, 22)}</>);
     const jvmMarkup = renderToStaticMarkup(<>{getDbIcon('jvm', undefined, 22)}</>);