feat: Add photo management features, duplicate detection, attempt limits, and admin deletion

- Add duplicate photo detection (file hash and URL checking)
- Add max attempts per photo with UI counter
- Simplify penalty system (auto-enable when points > 0)
- Prevent scores from going below 0
- Add admin photo deletion functionality
- Improve navigation with always-visible logout
- Prevent users from guessing their own photos

lib/utils.ts

@@ -0,0 +1,9 @@
+import bcrypt from "bcryptjs"
+
+export async function hashPassword(password: string): Promise<string> {
+  return bcrypt.hash(password, 10)
+}
+
+export function normalizeString(str: string): string {
+  return str.trim().toLowerCase()
+}