feat(admin): add admin panel with user management, daily puzzle CRUD, and activity graph

- Add admin page at /admin (restricted to ADMIN_EMAIL via proxy)
- Implement user ban/unban and deletion
- Add daily puzzle creation, modification, deletion
- Include 14-day activity chart with hover details
- Add User.banned field to schema and migrate database
- Block banned users from logging in
- Add ADMIN_EMAIL to .env.local configuration
- Update Prisma client after schema changes

lib/generated/prisma/internal/prismaNamespace.ts

@@ -744,6 +744,7 @@ export const UserScalarFieldEnum = {
   name: 'name',
   email: 'email',
   password: 'password',
+  banned: 'banned',
   createdAt: 'createdAt'
 } as const
 
@@ -811,6 +812,13 @@ export type StringFieldRefInput<$PrismaModel> = FieldRefInputType<$PrismaModel,
     
 
 
+/**
+ * Reference to a field of type 'Boolean'
+ */
+export type BooleanFieldRefInput<$PrismaModel> = FieldRefInputType<$PrismaModel, 'Boolean'>
+    
+
+
 /**
  * Reference to a field of type 'DateTime'
  */
@@ -831,13 +839,6 @@ export type IntFieldRefInput<$PrismaModel> = FieldRefInputType<$PrismaModel, 'In
 export type FloatFieldRefInput<$PrismaModel> = FieldRefInputType<$PrismaModel, 'Float'>
     
 
-
-/**
- * Reference to a field of type 'Boolean'
- */
-export type BooleanFieldRefInput<$PrismaModel> = FieldRefInputType<$PrismaModel, 'Boolean'>
-    
-
 /**
  * Batch Payload for updateMany & deleteMany & createMany
  */