test(FN-1282): expand dashboard hook and modal coverage

- Add tests for useAgents and useProjectHealth hooks, including loading, success, and error flows
- Add useFileBrowser and useFileEditor hook tests for file navigation, save behavior, and edge cases
- Add component tests for AgentImportModal and AgentGenerationModal interaction paths
- Add MissionInterviewModal tests covering question flow, submission, and state transitions
- Stabilize dashboard test suite cleanup and mocking patterns to reduce flakiness

packages/dashboard/app/hooks/__tests__/useFileBrowser.test.ts

@@ -0,0 +1,185 @@
+import { describe, it, expect, vi, beforeEach, afterEach } from "vitest";
+import { renderHook, act, waitFor } from "@testing-library/react";
+import { useFileBrowser } from "../useFileBrowser";
+import * as api from "../../api";
+import type { FileListResponse } from "../../api";
+
+vi.mock("../../api", () => ({
+  fetchFileList: vi.fn(),
+}));
+
+const mockFetchFileList = vi.mocked(api.fetchFileList);
+
+function response(path: string, names: string[]): FileListResponse {
+  return {
+    path,
+    entries: names.map((name) => ({
+      name,
+      type: name.includes(".") ? "file" : "directory",
+      mtime: "2026-01-01T00:00:00.000Z",
+      ...(name.includes(".") ? { size: 123 } : {}),
+    })),
+  };
+}
+
+describe("useFileBrowser", () => {
+  beforeEach(() => {
+    mockFetchFileList.mockReset();
+    mockFetchFileList.mockResolvedValue(response(".", ["src", "README.md"]));
+  });
+
+  afterEach(() => {
+    vi.clearAllMocks();
+  });
+
+  it("returns empty entries and loading=false when enabled=false", async () => {
+    const { result } = renderHook(() => useFileBrowser("FN-001", false));
+
+    expect(result.current.entries).toEqual([]);
+    expect(result.current.loading).toBe(false);
+    expect(result.current.error).toBeNull();
+
+    await new Promise((resolve) => setTimeout(resolve, 10));
+    expect(mockFetchFileList).not.toHaveBeenCalled();
+  });
+
+  it("returns empty entries and loading=false when taskId is empty", async () => {
+    const { result } = renderHook(() => useFileBrowser("", true));
+
+    expect(result.current.entries).toEqual([]);
+    expect(result.current.loading).toBe(false);
+
+    await new Promise((resolve) => setTimeout(resolve, 10));
+    expect(mockFetchFileList).not.toHaveBeenCalled();
+  });
+
+  it("fetches file list when enabled and sets loading then entries", async () => {
+    const { result } = renderHook(() => useFileBrowser("FN-001", true));
+
+    await waitFor(() => {
+      expect(result.current.loading).toBe(true);
+    });
+
+    await waitFor(() => {
+      expect(result.current.loading).toBe(false);
+      expect(result.current.entries).toHaveLength(2);
+    });
+  });
+
+  it("populates entries from FileListResponse", async () => {
+    mockFetchFileList.mockResolvedValueOnce(response(".", ["docs", "notes.md", "index.ts"]));
+
+    const { result } = renderHook(() => useFileBrowser("FN-001", true));
+
+    await waitFor(() => {
+      expect(result.current.entries.map((entry) => entry.name)).toEqual(["docs", "notes.md", "index.ts"]);
+    });
+  });
+
+  it("handles fetch error by setting error message and clearing entries", async () => {
+    mockFetchFileList.mockRejectedValueOnce(new Error("Failed to load files"));
+
+    const { result } = renderHook(() => useFileBrowser("FN-001", true));
+
+    await waitFor(() => {
+      expect(result.current.loading).toBe(false);
+      expect(result.current.error).toBe("Failed to load files");
+    });
+
+    expect(result.current.entries).toEqual([]);
+  });
+
+  it("setPath updates currentPath, clears error, and triggers new fetch", async () => {
+    mockFetchFileList
+      .mockRejectedValueOnce(new Error("boom"))
+      .mockResolvedValueOnce(response("src", ["index.ts"]));
+
+    const { result } = renderHook(() => useFileBrowser("FN-001", true));
+
+    await waitFor(() => {
+      expect(result.current.error).toBe("boom");
+    });
+
+    act(() => {
+      result.current.setPath("src");
+    });
+
+    expect(result.current.currentPath).toBe("src");
+    expect(result.current.error).toBeNull();
+
+    await waitFor(() => {
+      expect(mockFetchFileList).toHaveBeenLastCalledWith("FN-001", "src");
+      expect(result.current.entries.map((entry) => entry.name)).toEqual(["index.ts"]);
+    });
+  });
+
+  it("normalizes '.' path to undefined when calling fetchFileList", async () => {
+    const { result } = renderHook(() => useFileBrowser("FN-001", true));
+
+    await waitFor(() => {
+      expect(mockFetchFileList).toHaveBeenCalledWith("FN-001", undefined);
+    });
+
+    act(() => {
+      result.current.setPath(".");
+    });
+
+    await waitFor(() => {
+      expect(mockFetchFileList).toHaveBeenLastCalledWith("FN-001", undefined);
+    });
+  });
+
+  it("passes non-dot paths directly to fetchFileList", async () => {
+    const { result } = renderHook(() => useFileBrowser("FN-001", true));
+
+    await waitFor(() => {
+      expect(mockFetchFileList).toHaveBeenCalled();
+    });
+
+    act(() => {
+      result.current.setPath("subdir");
+    });
+
+    await waitFor(() => {
+      expect(mockFetchFileList).toHaveBeenLastCalledWith("FN-001", "subdir");
+    });
+  });
+
+  it("refresh increments refresh key and triggers re-fetch", async () => {
+    mockFetchFileList
+      .mockResolvedValueOnce(response(".", ["a.txt"]))
+      .mockResolvedValueOnce(response(".", ["a.txt", "b.txt"]));
+
+    const { result } = renderHook(() => useFileBrowser("FN-001", true));
+
+    await waitFor(() => {
+      expect(result.current.entries.map((entry) => entry.name)).toEqual(["a.txt"]);
+    });
+
+    act(() => {
+      result.current.refresh();
+    });
+
+    await waitFor(() => {
+      expect(result.current.entries.map((entry) => entry.name)).toEqual(["a.txt", "b.txt"]);
+      expect(mockFetchFileList).toHaveBeenCalledTimes(2);
+    });
+  });
+
+  it("cancels in-flight fetch on unmount", async () => {
+    let resolveFetch!: (value: FileListResponse) => void;
+    mockFetchFileList.mockReturnValueOnce(
+      new Promise<FileListResponse>((resolve) => {
+        resolveFetch = resolve;
+      }),
+    );
+
+    const { unmount } = renderHook(() => useFileBrowser("FN-001", true));
+    unmount();
+
+    resolveFetch(response(".", ["late.txt"]));
+
+    await new Promise((resolve) => setTimeout(resolve, 10));
+    expect(mockFetchFileList).toHaveBeenCalledTimes(1);
+  });
+});