feat(core): improve mixpanel (#7652)

move @affine/core/utils/mixpanel -> @affine/core/mixpanel

now you can debug mixpanel on browser devtool

![CleanShot 2024-07-30 at 17.32.48@2x.png](https://graphite-user-uploaded-assets-prod.s3.amazonaws.com/g3jz87HxbjOJpXV3FPT7/083c1286-39fd-4569-b4d2-e6e84cf2e797.png)

packages/frontend/core/src/utils/index.ts

@@ -1,6 +1,5 @@
 export * from './create-emotion-cache';
 export * from './fractional-indexing';
-export * from './mixpanel';
 export * from './popup';
 export * from './string2color';
 export * from './toast';

packages/frontend/core/src/utils/mixpanel.ts

@@ -1,42 +0,0 @@
-import { DebugLogger } from '@affine/debug';
-import type { OverridedMixpanel } from 'mixpanel-browser';
-import mixpanelBrowser from 'mixpanel-browser';
-
-import type { MixpanelEvents } from '../mixpanel';
-
-const logger = new DebugLogger('affine:mixpanel');
-
-export const mixpanel = process.env.MIXPANEL_TOKEN
-  ? mixpanelBrowser
-  : new Proxy(
-      function () {} as unknown as OverridedMixpanel,
-      createProxyHandler()
-    );
-
-function createProxyHandler(property?: string | symbol) {
-  const handler = {
-    get: (_target, childProperty) => {
-      const path = property
-        ? String(property) + '.' + String(childProperty)
-        : String(childProperty);
-      return new Proxy(
-        function () {} as unknown as OverridedMixpanel,
-        createProxyHandler(path)
-      );
-    },
-    apply: (_target, _thisArg, args) => {
-      logger.debug(
-        `mixpanel.${property ? String(property) : 'mixpanel'}`,
-        ...args
-      );
-    },
-  } as ProxyHandler<OverridedMixpanel>;
-  return handler;
-}
-
-export function mixpanelTrack<T extends keyof MixpanelEvents>(
-  event: T,
-  properties?: MixpanelEvents[T]
-) {
-  return mixpanel.track(event, properties);
-}