fix: less racy auth token refresh logic

This may help with issues reported by users where the access token is
invalid and can't be used to join servers over long periods of time.

packages/app-lib/src/state/minecraft_auth.rs

@@ -253,12 +253,16 @@ pub(super) static PROFILE_CACHE: Mutex<
 > = Mutex::const_new(HashMap::with_hasher(BuildHasherDefault::new()));
 
 impl Credentials {
-    /// Refreshes the authentication tokens for this user if they are expired.
+    /// Refreshes the authentication tokens for this user if they are expired, or
+    /// very close to expiration.
     async fn refresh(
         &mut self,
         exec: impl sqlx::Executor<'_, Database = sqlx::Sqlite> + Copy,
     ) -> crate::Result<()> {
-        if self.expires > Utc::now() {
+        // Use a margin of 5 minutes to give e.g. Minecraft and potentially
+        // other operations that depend on a fresh token 5 minutes to complete
+        // from now, and deal with some classes of clock skew
+        if self.expires > Utc::now() + Duration::minutes(5) {
             return Ok(());
         }