🐛 fix(sidebar): 修复视图元数据重复导致侧边栏树渲染错乱

- MySQL 视图元数据缺失 schema 时回填当前数据库
- 避免多条回退查询生成重复视图节点
- 补充侧边栏视图去重回归测试

frontend/src/components/sidebar/sidebarMetadataLoaders.test.ts

@@ -1,10 +1,17 @@
-import { describe, expect, it, vi } from "vitest";
+import { beforeEach, describe, expect, it, vi } from "vitest";
 
 vi.mock("../../../wailsjs/go/app/App", () => ({
   DBQuery: vi.fn(),
 }));
 
-import { buildSchemasMetadataQuerySpecs } from "./sidebarMetadataLoaders";
+import { DBQuery } from "../../../wailsjs/go/app/App";
+import { buildSchemasMetadataQuerySpecs, loadViews } from "./sidebarMetadataLoaders";
+
+const mockedDBQuery = vi.mocked(DBQuery);
+
+beforeEach(() => {
+  mockedDBQuery.mockReset();
+});
 
 describe("buildSchemasMetadataQuerySpecs", () => {
   it("returns schema queries for independent-schema targets", () => {
@@ -25,4 +32,35 @@ describe("buildSchemasMetadataQuerySpecs", () => {
   it("keeps unsupported dialects empty", () => {
     expect(buildSchemasMetadataQuerySpecs("mysql", "app")).toEqual([]);
   });
+
+  it("deduplicates MySQL view metadata when fallback queries omit schema names", async () => {
+    mockedDBQuery.mockImplementation(async (_config: unknown, _dbName: string, sql: string) => {
+      if (sql.includes("information_schema.views")) {
+        return {
+          success: true,
+          data: [{ view_name: "CHARACTER_SETS", schema_name: "information_schema" }],
+        };
+      }
+      if (sql.includes("information_schema.tables")) {
+        return {
+          success: true,
+          data: [{ view_name: "CHARACTER_SETS", schema_name: "information_schema", table_type: "SYSTEM VIEW" }],
+        };
+      }
+      if (sql.includes("SHOW FULL TABLES FROM `information_schema` WHERE Table_type = 'VIEW'")) {
+        return {
+          success: true,
+          data: [{ Tables_in_information_schema: "CHARACTER_SETS", Table_type: "VIEW" }],
+        };
+      }
+      return { success: false, data: [] };
+    });
+
+    const result = await loadViews({ config: { type: "mysql" } }, "information_schema");
+
+    expect(result.supported).toBe(true);
+    expect(result.views).toEqual([
+      { viewName: "CHARACTER_SETS", schemaName: "information_schema" },
+    ]);
+  });
 });