Prevent email autofill as display name and autosave profile media

Hop-State: A_06FP8EYP9H40CXQH16XPSN8
Hop-Proposal: R_06FP8EY0KW03D22K71DN4KG
Hop-Task: T_06FP8DNXSH7CAHXCHDZ2Z1R
Hop-Attempt: AT_06FP8DNXSKPDEVNXEZRQ5W8

src/app/api/auth/register/route.ts

@@ -9,7 +9,7 @@ const registerSchema = z.object({
     handle: z.string().min(3).max(20).regex(/^[a-zA-Z0-9_]+$/),
     email: z.string().email(),
     password: z.string().min(8),
-    displayName: z.string().optional(),
+    displayName: z.string().trim().max(50).optional(),
     turnstileToken: z.string().nullable().optional(),
 });