Reconnect to the Saturn server and time out requests

Move to session-java 0.2.0 (Gitea package registry) and rework
ServiceClient around a single connect loop:

- Reconnect with exponential backoff (1 s -> 60 s) when the connection
  drops, e.g. on every server redeploy; give up only when retrying cannot
  help (no Minecraft session, or the server rejects the token)
- Publish the session only after authentication succeeds, and replace
  (rather than append to) owned cosmetics and clear cached players on
  reconnect
- Time out every request after 10 s and connecting after 10 s, so a lost
  response can no longer hang the player-lookup worker forever
- Register onClientStopping once, and keep a local session reference in
  request callbacks
- Allow -Dsaturn.serverUri to point the client at a local server

Refs saturnclientmc/saturnclient#4, saturnclientmc/saturnclient#5

Co-Authored-By: Claude Opus 5.5 <[email protected]>

src/main/java/org/saturnclient/client/player/SaturnPlayer.java

@@ -78,6 +78,12 @@ public class SaturnPlayer {
         return get(name, Providers.saturn.getClient().getPlayerListEntryUUID(name));
     }
 
+    /** Forgets every cached player, e.g. after reconnecting to the server. */
+    public static void clear() {
+        PLAYERS.clear();
+        NEXT_LOOKUP.clear();
+    }
+
     public static void set(SaturnPlayer player) {
         PLAYERS.put(player.uuid, player);
         NEXT_LOOKUP.remove(player.uuid);