✨ feat(external-sql): 完善外部 SQL 目录文件管理

- 新增外部 SQL 文件的新建、重命名、删除和目录管理接口

- 后端限制 SQL 目录只加载 .sql 文件并补充目录操作测试

- 前端补齐 Wails 类型、浏览器 mock 和外部 SQL 树过滤逻辑

- 支持从外部 SQL 文件标签定位到侧栏目录节点

frontend/src/utils/externalSqlTree.test.ts

@@ -10,8 +10,6 @@ describe('externalSqlTree helpers', () => {
         id: 'dir-1',
         name: 'scripts',
         path: 'D:/sql/scripts',
-        connectionId: 'conn-1',
-        dbName: 'demo',
         createdAt: 1,
       },
     ];
@@ -33,14 +31,12 @@ describe('externalSqlTree helpers', () => {
     };
 
     const node = buildExternalSQLRootNode({
-      dbNodeKey: 'conn-1-demo',
-      connectionId: 'conn-1',
-      dbName: 'demo',
       directories,
       directoryTrees: trees,
     });
 
     expect(node.type).toBe('external-sql-root');
+    expect(node.key).toBe('external-sql-root');
     expect(node.title).toBe('外部 SQL 目录 (1)');
     expect(node.children).toHaveLength(1);
     expect(node.children?.[0]).toMatchObject({
@@ -65,4 +61,77 @@ describe('externalSqlTree helpers', () => {
     expect(first).toContain('demo');
     expect(first).not.toBe(second);
   });
+
+  it('filters non-sql file entries even when the backend returns them', () => {
+    const directories: ExternalSQLDirectory[] = [
+      {
+        id: 'dir-1',
+        name: 'scripts',
+        path: 'D:/sql/scripts',
+        createdAt: 1,
+      },
+    ];
+    const trees: Record<string, ExternalSQLTreeEntry[]> = {
+      'dir-1': [
+        {
+          name: 'readme.md',
+          path: 'D:/sql/scripts/readme.md',
+          isDir: false,
+        },
+        {
+          name: 'nested',
+          path: 'D:/sql/scripts/nested',
+          isDir: true,
+          children: [
+            {
+              name: 'notes.txt',
+              path: 'D:/sql/scripts/nested/notes.txt',
+              isDir: false,
+            },
+            {
+              name: 'report.SQL',
+              path: 'D:/sql/scripts/nested/report.SQL',
+              isDir: false,
+            },
+          ],
+        },
+        {
+          name: 'docs',
+          path: 'D:/sql/scripts/docs',
+          isDir: true,
+          children: [
+            {
+              name: 'manual.md',
+              path: 'D:/sql/scripts/docs/manual.md',
+              isDir: false,
+            },
+          ],
+        },
+      ],
+    };
+
+    const node = buildExternalSQLRootNode({
+      directories,
+      directoryTrees: trees,
+    });
+
+    const folderChildren = node.children?.[0].children || [];
+    const docsFolder = folderChildren.find((child) => child.title === 'docs');
+    const nestedFolder = folderChildren.find((child) => child.title === 'nested');
+    expect(folderChildren).toHaveLength(2);
+    expect(docsFolder).toMatchObject({
+      title: 'docs',
+      type: 'external-sql-folder',
+    });
+    expect(docsFolder?.children).toBeUndefined();
+    expect(nestedFolder).toMatchObject({
+      title: 'nested',
+      type: 'external-sql-folder',
+    });
+    expect(nestedFolder?.children).toHaveLength(1);
+    expect(nestedFolder?.children?.[0]).toMatchObject({
+      title: 'report.SQL',
+      type: 'external-sql-file',
+    });
+  });
 });