refactor: reorganize data/ and util/ into subpackages

- data/ (15 files) → config/ (6), reward/ (3), stats/ (4), FillMode (1)
- util/ (9 files) → location/ (3), selection/ (3), format/ (2)
- Updated all package declarations and imports
- Rule: ≤6 files per folder enforced

src/main/java/com/loki/lomines/data/LeaderboardEntry.java

@@ -1,45 +0,0 @@
-package com.loki.lomines.data;
-
-import java.util.Objects;
-import java.util.UUID;
-
-/**
- * Immutable data class representing a single entry in the leaderboard.
- * Contains a player's UUID and their block count.
- */
-public final class LeaderboardEntry {
-    
-    private final UUID playerId;
-    private final long count;
-    
-    public LeaderboardEntry(UUID playerId, long count) {
-        this.playerId = Objects.requireNonNull(playerId, "playerId cannot be null");
-        this.count = count;
-    }
-    
-    public UUID getPlayerId() {
-        return playerId;
-    }
-    
-    public long getCount() {
-        return count;
-    }
-    
-    @Override
-    public boolean equals(Object o) {
-        if (this == o) return true;
-        if (o == null || getClass() != o.getClass()) return false;
-        LeaderboardEntry that = (LeaderboardEntry) o;
-        return count == that.count && playerId.equals(that.playerId);
-    }
-    
-    @Override
-    public int hashCode() {
-        return Objects.hash(playerId, count);
-    }
-    
-    @Override
-    public String toString() {
-        return "LeaderboardEntry{playerId=" + playerId + ", count=" + count + "}";
-    }
-}