feat(KB-502): add dashboard multi-project hooks and project API routes

- Add project API routes for multi-project backend integration
- Create useProjects hook for listing and managing registered projects
- Create useCurrentProject hook for current project selection and switching
- Create useProjectHealth hook for real-time project health metrics
- Create useActivityLog hook with ActivityLogModal integration
- Add comprehensive test coverage for all hooks (useProjects, useCurrentProject, useActivityLog)
- Add test setup utilities for React Query mocking

packages/dashboard/app/hooks/useCurrentProject.test.ts

@@ -0,0 +1,178 @@
+import { describe, it, expect, vi, beforeEach, afterEach } from "vitest";
+import { renderHook, waitFor, act } from "@testing-library/react";
+import { useCurrentProject } from "./useCurrentProject";
+import type { ProjectInfo } from "../api";
+
+describe("useCurrentProject", () => {
+  const mockProjects: ProjectInfo[] = [
+    {
+      id: "proj_1",
+      name: "Project One",
+      path: "/path/one",
+      status: "active",
+      isolationMode: "in-process",
+      createdAt: "2026-01-01T00:00:00.000Z",
+      updatedAt: "2026-01-01T00:00:00.000Z",
+    },
+    {
+      id: "proj_2",
+      name: "Project Two",
+      path: "/path/two",
+      status: "paused",
+      isolationMode: "child-process",
+      createdAt: "2026-01-01T00:00:00.000Z",
+      updatedAt: "2026-01-01T00:00:00.000Z",
+    },
+  ];
+
+  beforeEach(() => {
+    localStorage.clear();
+    vi.clearAllMocks();
+  });
+
+  afterEach(() => {
+    localStorage.clear();
+  });
+
+  it("initializes with null when no saved project and no available projects", async () => {
+    const { result } = renderHook(() => useCurrentProject([]));
+
+    await waitFor(() => {
+      expect(result.current.loading).toBe(false);
+    });
+
+    expect(result.current.currentProject).toBeNull();
+  });
+
+  it("defaults to first active project when projects available but no selection", async () => {
+    const { result } = renderHook(() => useCurrentProject(mockProjects));
+
+    await waitFor(() => {
+      expect(result.current.loading).toBe(false);
+    });
+
+    // Should default to first active project
+    await waitFor(() => {
+      expect(result.current.currentProject?.id).toBe("proj_1");
+    });
+  });
+
+  it("loads saved project from localStorage", async () => {
+    localStorage.setItem("kb-dashboard-current-project", JSON.stringify(mockProjects[0]));
+
+    const { result } = renderHook(() => useCurrentProject(mockProjects));
+
+    await waitFor(() => {
+      expect(result.current.loading).toBe(false);
+    });
+
+    // After validation, it should have the saved project
+    await waitFor(() => {
+      expect(result.current.currentProject).not.toBeNull();
+    });
+  });
+
+  it("defaults to first active project when no selection", async () => {
+    const { result } = renderHook(() => useCurrentProject(mockProjects));
+
+    await waitFor(() => {
+      expect(result.current.loading).toBe(false);
+    });
+
+    // Should default to first active project
+    await waitFor(() => {
+      expect(result.current.currentProject?.id).toBe("proj_1");
+    });
+  });
+
+  it("clears selection when project no longer exists", async () => {
+    const unregisteredProject: ProjectInfo = {
+      id: "proj_old",
+      name: "Old Project",
+      path: "/old/path",
+      status: "active",
+      isolationMode: "in-process",
+      createdAt: "2026-01-01T00:00:00.000Z",
+      updatedAt: "2026-01-01T00:00:00.000Z",
+    };
+
+    localStorage.setItem("kb-dashboard-current-project", JSON.stringify(unregisteredProject));
+
+    const { result } = renderHook(() => useCurrentProject(mockProjects));
+
+    await waitFor(() => {
+      expect(result.current.loading).toBe(false);
+    });
+
+    // Should clear and default to first active
+    await waitFor(() => {
+      expect(result.current.currentProject?.id).toBe("proj_1");
+    });
+  });
+
+  it("setCurrentProject updates selection and saves to localStorage", async () => {
+    const { result } = renderHook(() => useCurrentProject(mockProjects));
+
+    await waitFor(() => {
+      expect(result.current.loading).toBe(false);
+    });
+
+    act(() => {
+      result.current.setCurrentProject(mockProjects[1]);
+    });
+
+    expect(result.current.currentProject?.id).toBe("proj_2");
+    expect(localStorage.getItem("kb-dashboard-current-project")).toContain("proj_2");
+  });
+
+  it("clearCurrentProject removes selection and re-defaults when projects available", async () => {
+    localStorage.setItem("kb-dashboard-current-project", JSON.stringify(mockProjects[1]));
+
+    const { result } = renderHook(() => useCurrentProject(mockProjects));
+
+    await waitFor(() => {
+      expect(result.current.loading).toBe(false);
+    });
+
+    // After loading, we should have proj_2 from localStorage
+    await waitFor(() => {
+      expect(result.current.currentProject?.id).toBe("proj_2");
+    });
+
+    act(() => {
+      result.current.clearCurrentProject();
+    });
+
+    // With available projects, it re-defaults to first active and saves to localStorage
+    await waitFor(() => {
+      expect(result.current.currentProject?.id).toBe("proj_1");
+    });
+    
+    // After re-defaulting, localStorage should have the default project
+    expect(localStorage.getItem("kb-dashboard-current-project")).toContain("proj_1");
+  });
+
+  it("handles localStorage errors gracefully", async () => {
+    // Mock localStorage to throw
+    const originalSetItem = localStorage.setItem;
+    localStorage.setItem = vi.fn(() => {
+      throw new Error("Storage error");
+    });
+
+    const { result } = renderHook(() => useCurrentProject(mockProjects));
+
+    await waitFor(() => {
+      expect(result.current.loading).toBe(false);
+    });
+
+    act(() => {
+      result.current.setCurrentProject(mockProjects[0]);
+    });
+
+    // Should still update state even if localStorage fails
+    expect(result.current.currentProject?.id).toBe("proj_1");
+
+    // Restore
+    localStorage.setItem = originalSetItem;
+  });
+});