fix: auth not working when accessed from non-localhost

- Remove hardcoded baseURL from auth-client.ts — better-auth now uses
  current window.location.origin, works from any IP/domain
- Add trustedOrigins config to auth.ts — allows requests from LAN IPs
- Add BETTER_AUTH_TRUSTED_ORIGINS env var for configuring allowed origins
- Improve error logging in login/register forms (was silent catch)

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

src/app/login/page.tsx

@@ -25,8 +25,9 @@ export default function LoginPage() {
       } else {
         router.push("/dashboard");
       }
-    } catch {
-      setError("Произошла ошибка. Попробуйте ещё раз.");
+    } catch (err) {
+      console.error("Login error:", err);
+      setError(err instanceof Error ? err.message : "Произошла ошибка. Попробуйте ещё раз.");
     } finally {
       setLoading(false);
     }

src/app/register/page.tsx

@@ -26,8 +26,9 @@ export default function RegisterPage() {
       } else {
         router.push("/dashboard");
       }
-    } catch {
-      setError("Произошла ошибка. Попробуйте ещё раз.");
+    } catch (err) {
+      console.error("Register error:", err);
+      setError(err instanceof Error ? err.message : "Произошла ошибка. Попробуйте ещё раз.");
     } finally {
       setLoading(false);
     }

src/lib/auth-client.ts

@@ -1,7 +1,5 @@
 import { createAuthClient } from "better-auth/react";
 
-export const authClient = createAuthClient({
-  baseURL: process.env.NEXT_PUBLIC_APP_URL || "http://localhost:3000",
-});
+export const authClient = createAuthClient();
 
 export const { signIn, signUp, signOut, useSession } = authClient;

src/lib/auth.ts

@@ -3,6 +3,10 @@ import { prismaAdapter } from "better-auth/adapters/prisma";
 import { prisma } from "./prisma";
 
 export const auth = betterAuth({
+  baseURL: process.env.BETTER_AUTH_URL,
+  trustedOrigins: process.env.BETTER_AUTH_TRUSTED_ORIGINS
+    ? process.env.BETTER_AUTH_TRUSTED_ORIGINS.split(",")
+    : ["http://localhost:3000"],
   database: prismaAdapter(prisma, {
     provider: "postgresql",
   }),