refactor: split MineConfig and Mines classes (291→182, 247→157 lines)

- Extract MineConfig.Builder → MineConfigBuilder (separate file)
- Split Mines into 3 services:
  * MineFileManager - file operations
  * MineRepository - CRUD operations
  * MaskScanService - mask scanning logic
- Fix imports: data.* → data.config.*

Progress: 2/7 files >200 lines fixed

src/main/java/com/loki/lomines/data/config/MineConfigBuilder.java

@@ -0,0 +1,128 @@
+package com.loki.lomines.data.config;
+
+import org.bukkit.Location;
+
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+
+/**
+ * Builder for creating immutable MineConfig instances.
+ */
+public final class MineConfigBuilder {
+    private List<Location> selections = new ArrayList<>();
+    private Map<String, Double> blocks = new HashMap<>();
+    private FillMode fillMode = FillMode.CUBOID;
+    private String maskMarkerMaterial = "pink_concrete";
+    private List<Location> maskPositions = new ArrayList<>();
+    private List<Reward> rewards = new ArrayList<>();
+    private int resetTicks = 6000;
+    private double resetPercent = 10.0;
+    private boolean resetOnPercentEnabled = false;
+    private List<String> resetCommands = new ArrayList<>();
+    private String broadcastReset = "";
+    private boolean teleportOnReset = false;
+    private Location teleportLocation = null;
+    private boolean actionBarEnabled = true;
+    private String actionBarMessage = "";
+    private double actionBarRange = 50.0;
+    private String timerFormat = "mm:ss";
+
+    MineConfigBuilder() {
+    }
+
+    public MineConfigBuilder selections(List<Location> selections) {
+        this.selections = new ArrayList<>(selections);
+        return this;
+    }
+
+    public MineConfigBuilder blocks(Map<String, Double> blocks) {
+        this.blocks = new HashMap<>(blocks);
+        return this;
+    }
+
+    public MineConfigBuilder fillMode(FillMode fillMode) {
+        this.fillMode = fillMode != null ? fillMode : FillMode.CUBOID;
+        return this;
+    }
+
+    public MineConfigBuilder maskMarkerMaterial(String maskMarkerMaterial) {
+        this.maskMarkerMaterial = maskMarkerMaterial != null ? maskMarkerMaterial : "pink_concrete";
+        return this;
+    }
+
+    public MineConfigBuilder maskPositions(List<Location> maskPositions) {
+        this.maskPositions = maskPositions != null ? new ArrayList<>(maskPositions) : new ArrayList<>();
+        return this;
+    }
+
+    public MineConfigBuilder rewards(List<Reward> rewards) {
+        this.rewards = new ArrayList<>(rewards);
+        return this;
+    }
+
+    public MineConfigBuilder resetTicks(int resetTicks) {
+        this.resetTicks = resetTicks;
+        return this;
+    }
+
+    public MineConfigBuilder resetPercent(double resetPercent) {
+        this.resetPercent = resetPercent;
+        return this;
+    }
+
+    public MineConfigBuilder resetOnPercentEnabled(boolean resetOnPercentEnabled) {
+        this.resetOnPercentEnabled = resetOnPercentEnabled;
+        return this;
+    }
+
+    public MineConfigBuilder resetCommands(List<String> resetCommands) {
+        this.resetCommands = new ArrayList<>(resetCommands);
+        return this;
+    }
+
+    public MineConfigBuilder broadcastReset(String broadcastReset) {
+        this.broadcastReset = broadcastReset;
+        return this;
+    }
+
+    public MineConfigBuilder teleportOnReset(boolean teleportOnReset) {
+        this.teleportOnReset = teleportOnReset;
+        return this;
+    }
+
+    public MineConfigBuilder teleportLocation(Location teleportLocation) {
+        this.teleportLocation = teleportLocation;
+        return this;
+    }
+
+    public MineConfigBuilder actionBarEnabled(boolean actionBarEnabled) {
+        this.actionBarEnabled = actionBarEnabled;
+        return this;
+    }
+
+    public MineConfigBuilder actionBarMessage(String actionBarMessage) {
+        this.actionBarMessage = actionBarMessage;
+        return this;
+    }
+
+    public MineConfigBuilder actionBarRange(double actionBarRange) {
+        this.actionBarRange = actionBarRange;
+        return this;
+    }
+
+    public MineConfigBuilder timerFormat(String timerFormat) {
+        this.timerFormat = timerFormat;
+        return this;
+    }
+
+    public MineConfig build() {
+        return new MineConfig(
+            selections, blocks, fillMode, maskMarkerMaterial, maskPositions,
+            rewards, resetTicks, resetPercent, resetOnPercentEnabled,
+            resetCommands, broadcastReset, teleportOnReset, teleportLocation,
+            actionBarEnabled, actionBarMessage, actionBarRange, timerFormat
+        );
+    }
+}