feat: add cloud save backend

prisma/schema/app.prisma

@@ -3,6 +3,10 @@ model ApplicationSettings {
 
     enabledAuthencationMechanisms AuthMec[]
     metadataProviders             String[]
+
+    saveSlotCountLimit   Int   @default(5)
+    saveSlotSizeLimit    Float @default(10) // MB
+    saveSlotHistoryLimit Int   @default(3)
 }
 
 enum Platform {

prisma/schema/client.prisma

@@ -1,6 +1,7 @@
 enum ClientCapabilities {
     PeerAPI    @map("peerAPI") // other clients can use the HTTP API to P2P with this client
     UserStatus @map("userStatus") // this client can report this user's status (playing, online, etc etc)
+    CloudSaves       @map("cloudSaves") // ability to save to save slots
 }
 
 // References a device
@@ -16,6 +17,8 @@ model Client {
     lastConnected DateTime
 
     peerAPI ClientPeerAPIConfiguration?
+
+    lastAccessedSaves SaveSlot[]
 }
 
 model ClientPeerAPIConfiguration {

prisma/schema/content.prisma

@@ -31,9 +31,10 @@ model Game {
     mImageLibrary  String[] // linked to objects in s3
 
     versions        GameVersion[]
-    libraryBasePath String            @unique // Base dir for all the game versions
-    
+    libraryBasePath String        @unique // Base dir for all the game versions
+
     collections CollectionEntry[]
+    saves       SaveSlot[]
 
     @@unique([metadataSource, metadataId], name: "metadataKey")
 }
@@ -48,9 +49,9 @@ model GameVersion {
 
     platform Platform
 
-    launchCommand String @default("") // Command to run to start. Platform-specific. Windows games on Linux will wrap this command in Proton/Wine
+    launchCommand String   @default("") // Command to run to start. Platform-specific. Windows games on Linux will wrap this command in Proton/Wine
     launchArgs    String[]
-    setupCommand  String @default("") // Command to setup game (dependencies and such)
+    setupCommand  String   @default("") // Command to setup game (dependencies and such)
     setupArgs     String[]
     onlySetup     Boolean  @default(false)
 
@@ -64,6 +65,26 @@ model GameVersion {
     @@id([gameId, versionName])
 }
 
+// A save slot for a game
+model SaveSlot {
+    gameId String
+    game   Game   @relation(fields: [gameId], references: [id], onDelete: Cascade)
+    userId String
+    user   User   @relation(fields: [userId], references: [id], onDelete: Cascade)
+    index  Int
+
+    createdAt DateTime @default(now())
+    playtime  Float    @default(0) // hours
+
+    lastUsedClientId String
+    lastUsedClient   Client @relation(fields: [lastUsedClientId], references: [id])
+
+    history          String[] // list of objects
+    historyChecksums String[] // list of hashes
+
+    @@id([gameId, userId, index], name: "id")
+}
+
 model Developer {
     id String @id @default(uuid())
 

prisma/schema/user.prisma

@@ -15,6 +15,8 @@ model User {
     articles      Article[]
 
     tokens APIToken[]
+
+    saves SaveSlot[]
 }
 
 model Notification {