feat: Memento avec dates, Markdown, reminders et auth

Tests Playwright validés ✅:
- Création de notes: OK
- Modification titre: OK
- Modification contenu: OK
- Markdown éditable avec preview: OK

Fonctionnalités:
- date-fns: dates relatives sur cards
- react-markdown + remark-gfm
- Markdown avec toggle edit/preview
- Recherche améliorée (titre/contenu/labels/checkItems)
- Reminder recurrence/location (schema)
- NextAuth.js + User/Account/Session
- userId dans Note (optionnel)
- 4 migrations créées

Ready for production + auth integration

keep-notes/prisma/schema.prisma

@@ -10,22 +10,82 @@ datasource db {
   url      = env("DATABASE_URL")
 }
 
+model User {
+  id            String    @id @default(cuid())
+  name          String?
+  email         String    @unique
+  emailVerified DateTime?
+  image         String?
+  accounts      Account[]
+  sessions      Session[]
+  notes         Note[]
+  createdAt     DateTime  @default(now())
+  updatedAt     DateTime  @updatedAt
+}
+
+model Account {
+  userId            String
+  type              String
+  provider          String
+  providerAccountId String
+  refresh_token     String?
+  access_token      String?
+  expires_at        Int?
+  token_type        String?
+  scope             String?
+  id_token          String?
+  session_state     String?
+ 
+  createdAt DateTime @default(now())
+  updatedAt DateTime @updatedAt
+ 
+  user User @relation(fields: [userId], references: [id], onDelete: Cascade)
+ 
+  @@id([provider, providerAccountId])
+}
+ 
+model Session {
+  sessionToken String   @unique
+  userId       String
+  expires      DateTime
+  user         User     @relation(fields: [userId], references: [id], onDelete: Cascade)
+ 
+  createdAt DateTime @default(now())
+  updatedAt DateTime @updatedAt
+}
+ 
+model VerificationToken {
+  identifier String
+  token      String
+  expires    DateTime
+ 
+  @@id([identifier, token])
+}
+
 model Note {
-  id          String   @id @default(cuid())
-  title       String?
-  content     String
-  color       String   @default("default")
-  isPinned    Boolean  @default(false)
-  isArchived  Boolean  @default(false)
-  type        String   @default("text") // "text" or "checklist"
-  checkItems  String?  // For checklist items stored as JSON string
-  labels      String?  // Array of label names stored as JSON string
-  images      String?  // Array of image URLs stored as JSON string
-  order       Int      @default(0)
-  createdAt   DateTime @default(now())
-  updatedAt   DateTime @updatedAt
+  id                  String    @id @default(cuid())
+  title               String?
+  content             String
+  color               String    @default("default")
+  isPinned            Boolean   @default(false)
+  isArchived          Boolean   @default(false)
+  type                String    @default("text") // "text" or "checklist"
+  checkItems          String?   // For checklist items stored as JSON string
+  labels              String?   // Array of label names stored as JSON string
+  images              String?   // Array of image URLs stored as JSON string
+  reminder            DateTime? // Reminder date and time
+  reminderRecurrence  String?   // "none", "daily", "weekly", "monthly", "custom"
+  reminderLocation    String?   // Location for location-based reminders
+  isMarkdown          Boolean   @default(false) // Whether content uses Markdown
+  userId              String?   // Owner of the note (optional for now, will be required after auth)
+  user                User?     @relation(fields: [userId], references: [id], onDelete: Cascade)
+  order               Int       @default(0)
+  createdAt           DateTime  @default(now())
+  updatedAt           DateTime  @updatedAt
 
   @@index([isPinned])
   @@index([isArchived])
   @@index([order])
+  @@index([reminder])
+  @@index([userId])
 }