refactor: migrate package from com.loki to dev.loki

- Change base package from com.loki to dev.loki across all Java files
- Update plugin.yml main class path
- Fix ConfigParseException imports in test files
- Update build.gradle.kts relocate patterns
- Add missing imports in ConfigLoaderTest.java
- Update TODO.md with current status

BREAKING CHANGE: Package namespace changed from com.loki to dev.loki

src/main/java/dev/loki/lomines/command/MaskCommands.java

@@ -0,0 +1,49 @@
+package dev.loki.lomines.command;
+
+import dev.loki.lomines.LoMinesPlugin;
+import dev.loki.lomines.core.Mines;
+import dev.loki.lomines.data.config.parser.ConfigParseException;
+import dev.loki.lomines.util.ErrorHandler;
+import dev.loki.lomines.util.MessageFormatter;
+import dev.lolib.commands.annotation.Arg;
+import dev.lolib.commands.annotation.Command;
+import dev.lolib.commands.annotation.Subcommand;
+import dev.lolib.scheduler.Scheduler;
+import org.bukkit.command.CommandSender;
+
+import java.io.IOException;
+
+/**
+ * Mask commands for mine shape management.
+ * Provides commands for scanning and saving mask positions.
+ */
+@Command(value = "lm", permission = "lomines.use")
+public class MaskCommands {
+
+    private final LoMinesPlugin plugin;
+    private final Mines mines;
+    private final ErrorHandler errorHandler;
+
+    public MaskCommands(LoMinesPlugin plugin) {
+        this.plugin = plugin;
+        this.mines = plugin.getMines();
+        this.errorHandler = new ErrorHandler(plugin.getLogger(), "[LoMines] ");
+    }
+
+    @Subcommand(value = "maskscan", permission = "lomines.admin.maskscan")
+    public void maskScan(CommandSender sender, @Arg("mine") String name) {
+        Scheduler.get(plugin).run(() -> {
+            try {
+                int n = mines.scanAndSaveMask(name);
+                sender.sendMessage(MessageFormatter.success(
+                        "Mask mode: saved " + n + " cell(s) for mine '" + name
+                                + "'. Reset will spawn ore only at those positions."));
+            } catch (IllegalArgumentException e) {
+                errorHandler.handleNotFound(sender, "Mine", name);
+            } catch (IOException | ConfigParseException e) {
+                errorHandler.handleError(sender, "Mask scan failed: " + e.getMessage(),
+                        "maskscan failed for " + name, e);
+            }
+        });
+    }
+}