Clean repo for open source release

Remove build artifacts, dev tool configs, unused dependencies,
and third-party source dumps. Add proper README, update .gitignore,
clean up Makefile.

src/main/java/com/tiedup/remake/items/ItemCellKey.java

@@ -0,0 +1,55 @@
+package com.tiedup.remake.items;
+
+import java.util.List;
+import javax.annotation.Nullable;
+import net.minecraft.ChatFormatting;
+import net.minecraft.network.chat.Component;
+import net.minecraft.world.item.Item;
+import net.minecraft.world.item.ItemStack;
+import net.minecraft.world.item.TooltipFlag;
+import net.minecraft.world.level.Level;
+
+/**
+ * Cell Key - Universal key for iron bar doors.
+ *
+ * Phase: Kidnapper Revamp - Cell System
+ *
+ * Unlike regular keys which have UUIDs and can only unlock matching locks,
+ * the Cell Key can unlock any iron bar door regardless of which key locked it.
+ *
+ * This is a convenience item for kidnappers to manage their cells without
+ * needing to track individual keys.
+ *
+ * Does NOT unlock regular bondage items (collars, cuffs, etc.) - only iron bar doors.
+ */
+public class ItemCellKey extends Item {
+
+    public ItemCellKey() {
+        super(new Item.Properties().stacksTo(1));
+    }
+
+    @Override
+    public void appendHoverText(
+        ItemStack stack,
+        @Nullable Level level,
+        List<Component> tooltip,
+        TooltipFlag flag
+    ) {
+        tooltip.add(
+            Component.literal("Unlocks any Iron Bar Door").withStyle(
+                ChatFormatting.GRAY
+            )
+        );
+        tooltip.add(
+            Component.literal("Does not work on bondage items").withStyle(
+                ChatFormatting.DARK_GRAY
+            )
+        );
+    }
+
+    @Override
+    public boolean isFoil(ItemStack stack) {
+        // Slight shimmer to indicate it's a special key
+        return true;
+    }
+}