feat: configure authenticated player entry routes

plugins/shared/src/main/java/best/lolicon/felis/link/EntryPolicy.java

@@ -0,0 +1,29 @@
+package best.lolicon.felis.link;
+
+import java.util.Map;
+
+/** Owner-selected entry routing; authentication remains the proxy's responsibility. */
+public record EntryPolicy(String mode, String defaultServer, boolean requireAccountLink,
+                          String offlineAction, String waitingSpace, String fallbackServer) {
+    public static EntryPolicy legacy() {
+        return new EntryPolicy("domain", "", true, "wake", "lobby", "");
+    }
+
+    public static EntryPolicy fromJson(Map<?, ?> data) throws LinkException {
+        String mode = text(data, "mode");
+        String action = text(data, "offlineAction");
+        String space = text(data, "waitingSpace");
+        if (!(mode.equals("lobby") || mode.equals("direct") || mode.equals("domain"))
+                || !(action.equals("wake") || action.equals("fallback") || action.equals("disconnect"))
+                || !(space.equals("login") || space.equals("lobby"))
+                || !(data.get("requireAccountLink") instanceof Boolean)) {
+            throw new LinkException(503, "entry_policy_unavailable", "Invalid player entry policy");
+        }
+        return new EntryPolicy(mode, text(data, "defaultServer"), (boolean) data.get("requireAccountLink"),
+                action, space, text(data, "fallbackServer"));
+    }
+
+    private static String text(Map<?, ?> data, String key) {
+        return data.get(key) instanceof String value ? value : "";
+    }
+}

plugins/shared/src/main/java/best/lolicon/felis/link/FelisApiClient.java

@@ -69,6 +69,10 @@ public final class FelisApiClient {
         return stats;
     }
 
+    public EntryPolicy entryPolicy() throws LinkException {
+        return EntryPolicy.fromJson(getObject("/api/v1/internal/settings/entry-policy", 200));
+    }
+
     /** listServers returns the lifecycle view of every MinecraftServer (GET /servers). */
     public List<ServerView> listServers() throws LinkException {
         return ServerView.listFrom(getObject("/api/v1/servers", 200));