test(coverage): bootstrap vitest unit infra and add tests at 90%+ per file (#1245) (#1269)

* test(coverage): bootstrap vitest unit infra and add tests at 90%+ per file (#1245)

Establishes the unit-test runtime AGENTS.md mandates: a vitest "unit"
project alongside the existing storybook project, RTL + jest-dom +
happy-dom, a Mantine-aware render helper, and a 90%-line per-file
coverage gate enforced by CI. Adds 66 test files covering all 62
components under elements/groups/screens/views, plus core/mcp and
clients/web/src/utils. Total: 577 tests, 98.7% line coverage globally.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

* test(coverage): address PR #1269 review feedback

- AGENTS.md: correct coverage gate description (lines ≥ 90, statements ≥ 85,
  functions ≥ 80, branches ≥ 50) with rationale for the relaxed branch
  threshold
- InspectorView.test.tsx: document what the Math.random() mock values
  (0.1 / 0.99) control vs. STUB_SUCCESS_RATE in InspectorView.tsx
- vite.config.ts / tsconfig.test.json: drop unused `globals: true` and the
  `vitest/globals` type now that every test file imports describe/it/expect/vi
  explicitly; manual `afterEach(cleanup)` in setup.ts remains required because
  testing-library auto-cleanup relies on globalThis.afterEach

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

---------

Co-authored-by: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

clients/web/src/components/screens/ToolsScreen/ToolsScreen.test.tsx

@@ -0,0 +1,116 @@
+import { describe, it, expect, vi } from "vitest";
+import userEvent from "@testing-library/user-event";
+import type { Tool } from "@modelcontextprotocol/sdk/types.js";
+import { renderWithMantine, screen } from "../../../test/renderWithMantine";
+import { ToolsScreen } from "./ToolsScreen";
+
+const tools: Tool[] = [
+  { name: "alpha", inputSchema: { type: "object" } },
+  { name: "beta", inputSchema: { type: "object" } },
+];
+
+const baseProps = {
+  tools,
+  listChanged: false,
+  onRefreshList: vi.fn(),
+  onCallTool: vi.fn(),
+};
+
+describe("ToolsScreen", () => {
+  it("renders the empty selection state", () => {
+    renderWithMantine(<ToolsScreen {...baseProps} />);
+    expect(
+      screen.getByText("Select a tool to view details"),
+    ).toBeInTheDocument();
+    expect(screen.getByText("Results will appear here")).toBeInTheDocument();
+  });
+
+  it("shows the detail panel when a tool is selected", async () => {
+    const user = userEvent.setup();
+    renderWithMantine(<ToolsScreen {...baseProps} />);
+    await user.click(screen.getByText("alpha"));
+    expect(
+      screen.queryByText("Select a tool to view details"),
+    ).not.toBeInTheDocument();
+  });
+
+  it("renders the result panel when callState has a result", () => {
+    renderWithMantine(
+      <ToolsScreen
+        {...baseProps}
+        callState={{
+          status: "ok",
+          result: { content: [{ type: "text", text: "ok" }] },
+        }}
+      />,
+    );
+    expect(screen.getByText("Results")).toBeInTheDocument();
+  });
+
+  it("invokes onCallTool with form values on Execute", async () => {
+    const user = userEvent.setup();
+    const onCallTool = vi.fn();
+    renderWithMantine(<ToolsScreen {...baseProps} onCallTool={onCallTool} />);
+    await user.click(screen.getByText("alpha"));
+    await user.click(screen.getByRole("button", { name: /Execute/ }));
+    expect(onCallTool).toHaveBeenCalledWith("alpha", {});
+  });
+
+  it("invokes onClearResult when Clear is clicked on the result panel", async () => {
+    const user = userEvent.setup();
+    const onClearResult = vi.fn();
+    renderWithMantine(
+      <ToolsScreen
+        {...baseProps}
+        onClearResult={onClearResult}
+        callState={{
+          status: "ok",
+          result: { content: [{ type: "text", text: "ok" }] },
+        }}
+      />,
+    );
+    await user.click(screen.getByRole("button", { name: "Clear" }));
+    expect(onClearResult).toHaveBeenCalledTimes(1);
+  });
+
+  it("treats pending callState as executing", async () => {
+    const user = userEvent.setup();
+    renderWithMantine(
+      <ToolsScreen {...baseProps} callState={{ status: "pending" }} />,
+    );
+    await user.click(screen.getByText("alpha"));
+    expect(screen.getByRole("button", { name: /Cancel/ })).toBeInTheDocument();
+  });
+
+  it("invokes onCancelCall when Cancel is clicked", async () => {
+    const user = userEvent.setup();
+    const onCancelCall = vi.fn();
+    renderWithMantine(
+      <ToolsScreen
+        {...baseProps}
+        onCancelCall={onCancelCall}
+        callState={{ status: "pending" }}
+      />,
+    );
+    await user.click(screen.getByText("alpha"));
+    await user.click(screen.getByRole("button", { name: /Cancel/ }));
+    expect(onCancelCall).toHaveBeenCalledTimes(1);
+  });
+
+  it("does not crash when onClearResult/onCancelCall are undefined", async () => {
+    const user = userEvent.setup();
+    renderWithMantine(
+      <ToolsScreen
+        {...baseProps}
+        onCancelCall={undefined}
+        onClearResult={undefined}
+        callState={{
+          status: "ok",
+          result: { content: [{ type: "text", text: "ok" }] },
+        }}
+      />,
+    );
+    await user.click(screen.getByRole("button", { name: "Clear" }));
+    expect(screen.getByText("Results")).toBeInTheDocument();
+  });
+});