add: user grants

TODO: add grant creation api, grant tab in sessions tab of settings, grant api endpoints

crates/core/src/model/auth.rs

@@ -1,6 +1,6 @@
 use std::collections::HashMap;
 
-use super::permissions::FinePermission;
+use super::{oauth::AuthGrant, permissions::FinePermission};
 use serde::{Deserialize, Serialize};
 use totp_rs::TOTP;
 use tetratto_shared::{
@@ -43,6 +43,9 @@ pub struct User {
     /// The user's Stripe customer ID.
     #[serde(default)]
     pub stripe_id: String,
+    /// The grants associated with the user's account.
+    #[serde(default)]
+    pub grants: Vec<AuthGrant>,
 }
 
 pub type UserConnections =
@@ -251,6 +254,7 @@ impl User {
             request_count: 0,
             connections: HashMap::new(),
             stripe_id: String::new(),
+            grants: Vec::new(),
         }
     }