docs: use type-only import for BetterAuthClientPlugin (#7565)

Co-authored-by: Alex Yang <himself65@outlook.com>

docs/content/docs/concepts/plugins.mdx

@@ -461,7 +461,7 @@ const myPlugin = () => {
 If your endpoints need to be called from the client, you'll also need to create a client plugin. Better Auth clients can infer the endpoints from the server plugins. You can also add additional client-side logic.
 
 ```ts title="client-plugin.ts"
-import type { BetterAuthClientPlugin } from "better-auth";
+import type { BetterAuthClientPlugin } from "better-auth/client";
 
 export const myPluginClient = () => {
     return {

docs/content/docs/guides/your-first-plugin.mdx

@@ -164,7 +164,7 @@ First, let’s create our `client.ts` file first:
 </Files>
 Then, add the following code:
 ```ts title="client.ts"
-import { BetterAuthClientPlugin } from "better-auth";
+import type { BetterAuthClientPlugin } from "better-auth/client";
 import type { birthdayPlugin } from "./index"; // make sure to import the server plugin as a type // [!code highlight]
 
 type BirthdayPlugin = typeof birthdayPlugin;

packages/scim/src/client.ts

@@ -1,4 +1,4 @@
-import type { BetterAuthClientPlugin } from "better-auth";
+import type { BetterAuthClientPlugin } from "better-auth/client";
 import type { scim } from "./index";
 
 export const scimClient = () => {

packages/sso/src/client.ts

@@ -1,4 +1,4 @@
-import type { BetterAuthClientPlugin } from "better-auth";
+import type { BetterAuthClientPlugin } from "better-auth/client";
 import type { SSOPlugin } from "./index";
 
 interface SSOClientOptions {

packages/stripe/src/client.ts

@@ -1,4 +1,4 @@
-import type { BetterAuthClientPlugin } from "better-auth";
+import type { BetterAuthClientPlugin } from "better-auth/client";
 import type { stripe } from "./index";
 
 export const stripeClient = <

test/unit/types/index.test.ts

@@ -1,7 +1,12 @@
 import type { BetterAuthOptions } from "@better-auth/core";
 import type { Auth, InferUser } from "better-auth";
+import type { AuthClient } from "better-auth/client";
 import { expectTypeOf, test } from "vitest";
 
+test("expect imports", async () => {
+	expectTypeOf<AuthClient<{}>>().not.toBeUndefined();
+});
+
 test("infer user type correctly", async () => {
 	const config = {
 		user: {