feat(auth): include subscription tier in token and session payload

- Adds subscription tier info to access/refresh tokens.
- Stores tier details in session Redis record.
- Returns tier data in login/register response.
- Uses default tier when user has none.

prisma/schema.prisma

@@ -7,6 +7,41 @@ datasource db {
   url      = env("DATABASE_URL_APP")
 }
 
+model SubscriptionTier {
+  subscription_tier_id Int                         @id @default(autoincrement())
+  name                 String                      @db.VarChar(100)
+  slug                 String                      @unique @db.VarChar(50)
+  description          String?                     @db.Text
+  level                Int                         @default(0)
+  price_monthly        Decimal?                    @db.Decimal(10, 2)
+  price_yearly         Decimal?                    @db.Decimal(10, 2)
+  is_active            Boolean                     @default(true)
+  created_at           DateTime                    @default(now())
+  updated_at           DateTime                    @default(now()) @updatedAt
+  users                User[]
+  features             SubscriptionTierFeature[]
+
+  @@index([slug])
+  @@index([level])
+  @@map("subscription_tiers")
+}
+
+model SubscriptionTierFeature {
+  feature_id           Int               @id @default(autoincrement())
+  subscription_tier_id Int
+  feature_key          String            @db.VarChar(100)
+  label                String            @db.VarChar(255)
+  description          String?           @db.Text
+  sort_order           Int               @default(0)
+  created_at           DateTime          @default(now())
+  updated_at           DateTime          @default(now()) @updatedAt
+  tier                 SubscriptionTier  @relation(fields: [subscription_tier_id], references: [subscription_tier_id], onDelete: Cascade)
+
+  @@unique([subscription_tier_id, feature_key], map: "subscription_tier_features_unique")
+  @@index([subscription_tier_id, sort_order], map: "subscription_tier_features_sort_idx")
+  @@map("subscription_tier_features")
+}
+
 model User {
   user_id               Int      @id @default(autoincrement())
   username              String   @unique @db.VarChar(50)
@@ -35,10 +70,13 @@ model User {
   favorites             UserFavorite[]
   telemetry_events      TelemetryEvent[]
   purchaseIntentions    PurchaseIntention[] @relation("BuyerIntentions")
+  subscription_tier_id  Int?
+  subscription_tier     SubscriptionTier? @relation(fields: [subscription_tier_id], references: [subscription_tier_id], onDelete: SetNull)
 
   @@index([email])
   @@index([username])
   @@index([cpf])
+  @@index([subscription_tier_id])
   @@map("users")
 }