[Suggestion] Export MSW handlers from the Mixpanel package

[alexasselin008]

It would be helpful if the Mixpanel package exported MSW handlers to mock its network calls. This would simplify testing for teams using Mock Service Worker and reduce the need to reimplement or maintain custom mocks. Ideally, the package would also expose the relevant endpoint URLs, all types needed to mock those requests and responses for teams not using MSW,

[alexasselin008]

I'll try to have copilot code this PR. HEre is how we did it in another repository, to help do the same thing in this one:
Overview
This repository exports MSW handlers through a clean, organized pattern that separates concerns into URLs, Mocks, and Handlers, then combines them into widget-specific functions.

1. API URLs Definition
   File: [navigationApiRequests.ts]

// Generated by Copilot - URL configuration per environment
export const OrganizationManagementApiBaseUrl: Record<EnvironmentValue, string> = {
    "production": "https://api.management.workleap.com/organizationalManagement/",
    "staging": "https://api.management.workleap-stg.com/organizationalManagement/",
    "development": "https://api.management.workleap-dev.com/organizationalManagement/",
    "local": "https://local-management.workleap-dev.com:49151/",
    "msw": "/api/organizational/" // MSW-specific endpoints
};

export const OrganizationManagementApiUrls = (environment: EnvironmentValue) => ({
    Members: {
        Root: resolveUrl("/members", OrganizationManagementApiBaseUrl[environment]),
        ValidateEmails: resolveUrl("/members/validate-emails", OrganizationManagementApiBaseUrl[environment])
    }
});

2. Mock Data Generation
   File: navigationApiMocks.ts

// Generated by Copilot - Structured mock data with variants
export const NavigationApiMocks = {
    HeaderData: {
        Default: (): HeaderData => ({
            userInfo: getUserInfo(),
            products: getManyAssignedMemberProducts(),
            organizations: getOrganizations()
        }),
        SingleAssignedProduct: (): HeaderData => ({
            ...NavigationApiMocks.HeaderData.Default(),
            products: getSingleAssignedProduct()
        }),
        AllProductsInTrial: (): HeaderData => ({
            ...NavigationApiMocks.HeaderData.Default(),
            products: getManyAssignedMemberProducts(26, false, true)
        }),
        // Multiple variants for different test scenarios
        Custom: (data?: Partial<HeaderData>) => {
            const defaultValue = NavigationApiMocks.HeaderData.Default();
            return { ...defaultValue, ...data };
        }
    }
};

3. MSW Handlers Definition
   File: navigationApiHandlers.ts

// Generated by Copilot - HTTP handlers using MSW
export const NavigationApiHandlers = {
    HeaderData: {
        Default: http.get(MswNavigationApiUrls.HeaderData, async () => {
            await delay();
            const data = NavigationApiMocks.HeaderData.Default();
            return HttpResponse.json(data);
        }),
        AllProductsInTrial: http.get(MswNavigationApiUrls.HeaderData, async () => {
            await delay();
            const data = NavigationApiMocks.HeaderData.AllProductsInTrial();
            return HttpResponse.json(data);
        }),
        // Flexible custom handler
        Custom: (data?: Partial<HeaderData>) => {
            return http.get(MswNavigationApiUrls.HeaderData, async () => {
                await delay();
                const defaultValue = NavigationApiMocks.HeaderData.Default();
                return HttpResponse.json({ ...defaultValue, ...data });
            });
        }
    },
    Tracking: {
        Track: {
            Default: http.post(MswNavigationApiUrls.Tracking.Track, async () => {
                await delay();
                return HttpResponse.json(null);
            })
        }
    }
} satisfies HttpHandlerMap;

4. Widget-Specific Handler Functions
   File: navbarHandlers.ts

// Generated by Copilot - Composable handler functions
export interface GetNavbarHandlersOptions extends SessionInfo {
    // Widget-specific options
}

export function getNavbarHandlers(options: GetNavbarHandlersOptions = {}) {
    const navbarHandlers = [
        NavigationApiHandlers.HeaderData.Custom(options?.session),
        NavigationApiHandlers.Tracking.Track.Default
    ];

    // Integration with external handlers
    const aiHandlers = getAiHandlers({
        showTeaser: true,
        isAssigned: true
    });

    return [
        ...navbarHandlers,
        ...aiHandlers
    ];
}

5. Public API Export
   File: index.ts (presumably)

// Generated by Copilot - Clean public API
export { getNavbarHandlers } from "./navigation/navbarHandlers.ts";
export { getSidebarHandlers } from "./navigation/sidebarHandlers.ts"; // If exists
export { NavigationApiHandlers } from "./navigationApiHandlers.ts";
export { NavigationApiMocks } from "../mocks/navigationApiMocks.ts";

Key Benefits of This Pattern:
Environment-aware URLs - Same endpoints work across all environments
Composable mocks - Mix and match different data scenarios
Flexible handlers - Support both predefined and custom responses
Widget-specific exports - Easy integration for consumers
Type safety - Full TypeScript support throughout
Delay simulation - Realistic network timing
External integration - Can combine with other MSW handlers

Usage Example:
This pattern makes it easy for consuming applications to mock your APIs with realistic data and flexible configuration options.

// Generated by Copilot - Consumer usage
import { getNavbarHandlers } from "@your-package/msw";

const worker = setupWorker(
    ...getNavbarHandlers({
        session: { userRole: "admin" }
    })
);

MSW as Optional Peer Dependency
This repository demonstrates a clean approach to MSW integration by making it an optional peer dependency:

// Generated by Copilot - Package.json configuration
{
  "peerDependencies": {
    "msw": "^2.10.2"
  },
  "peerDependenciesMeta": {
    "msw": {
      "optional": true
    }
  }
}

Benefits of This Approach:

1. Conditional MSW Export
   The package provides a separate export path for MSW functionality:

// Generated by Copilot - Separate MSW export
"exports": {
  ".": "./src/js/index.ts",           // Core API functionality
  "./react": "./src/react/index.ts",  // React hooks
  "./mocks": "./src/mocks/index.ts",  // Mock data only
  "./msw": "./src/msw/index.ts"       // MSW handlers (requires msw)
}

2. No Forced MSW Installation
   Consumers who only need the API calls don't have to install MSW
   Only projects that want to mock APIs need to install msw as their own dependency
   Reduces bundle size for production applications
3. Clean Separation of Concerns

// Generated by Copilot - Usage examples

// Production code - no MSW needed
import { fetchHeaderData } from "@workleap-widgets/api";

// Mock data only - no MSW needed  
import { NavigationApiMocks } from "@workleap-widgets/api/mocks";

// Full MSW integration - requires msw installed
import { getNavbarHandlers } from "@workleap-widgets/api/msw";

4. Tree-Shaking FriendlyThe optional dependency ensures that MSW code is completely excluded from production bundles when not explicitly imported, even if the package is installed.
   This pattern allows the repository to provide comprehensive MSW support without forcing all consumers to include MSW-related code in their applications, making it a great model for other repositories to follow.

[patricklafrance]

Depends on #137