revert: 回退 getInternalOrigin 改动，修复微信登录后无法跳转的问题

4dd36a9 将 middleware 内部 fetch 改为 http://localhost，导致请求
缺少 Host/x-forwarded-for 头，rate limiter 和 Better Auth 无法
正确识别客户端，session 检查始终失败。回退为直接使用
req.nextUrl.origin，在 Zeabur 部署环境下无 SSL 问题。

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: makerjackie

packages/lib-shared/src/middleware-helpers.ts

@@ -11,25 +11,12 @@ export interface Organization {
 	[key: string]: unknown;
 }
 
-/**
- * Get the internal origin for middleware self-referencing fetch calls.
- * In Docker/production behind a reverse proxy, req.nextUrl.origin is the
- * external HTTPS URL, but the container only serves HTTP. Using localhost
- * avoids SSL issues and is more efficient (no network round trip).
- */
-function getInternalOrigin(requestOrigin: string): string {
-	// On Vercel, edge middleware can use the request origin directly
-	if (process.env.NEXT_PUBLIC_VERCEL_URL) {
-		return requestOrigin;
-	}
-	// In Docker/self-hosted environments, use localhost to avoid SSL issues
-	return `http://localhost:${process.env.PORT ?? 3000}`;
-}
-
 export const getSession = async (req: NextRequest): Promise<Session | null> => {
-	const origin = getInternalOrigin(req.nextUrl.origin);
 	const response = await fetch(
-		new URL("/api/auth/get-session?disableCookieCache=true", origin),
+		new URL(
+			"/api/auth/get-session?disableCookieCache=true",
+			req.nextUrl.origin,
+		),
 		{
 			headers: {
 				cookie: req.headers.get("cookie") || "",
@@ -53,9 +40,8 @@ export const getSession = async (req: NextRequest): Promise<Session | null> => {
 export const getOrganizationsForSession = async (
 	req: NextRequest,
 ): Promise<Organization[]> => {
-	const origin = getInternalOrigin(req.nextUrl.origin);
 	const response = await fetch(
-		new URL("/api/auth/organization/list", origin),
+		new URL("/api/auth/organization/list", req.nextUrl.origin),
 		{
 			headers: {
 				cookie: req.headers.get("cookie") || "",