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/client/state/CollarRegistryClient.java

@@ -0,0 +1,98 @@
+package com.tiedup.remake.client.state;
+
+import java.util.Collections;
+import java.util.Set;
+import java.util.UUID;
+import java.util.concurrent.ConcurrentHashMap;
+import net.minecraftforge.api.distmarker.Dist;
+import net.minecraftforge.api.distmarker.OnlyIn;
+
+/**
+ * Client-side cache for collar registry data.
+ *
+ * This cache stores the UUIDs of slaves (collar wearers) owned by the local player.
+ * It is synchronized from the server via PacketSyncCollarRegistry.
+ *
+ * Used by SlaveManagementScreen to display owned slaves without spatial queries.
+ *
+ * Phase 17: Terminology Refactoring - Global Collar Registry
+ */
+@OnlyIn(Dist.CLIENT)
+public class CollarRegistryClient {
+
+    // Set of slave (collar wearer) UUIDs owned by the local player
+    private static final Set<UUID> ownedSlaves = ConcurrentHashMap.newKeySet();
+
+    // ==================== SYNC FROM SERVER ====================
+
+    /**
+     * Full sync: Replace all known slaves with the provided set.
+     * Called when player logs in or for full registry refresh.
+     */
+    public static void setSlaves(Set<UUID> slaveUUIDs) {
+        ownedSlaves.clear();
+        ownedSlaves.addAll(slaveUUIDs);
+    }
+
+    /**
+     * Incremental update: Add and remove specific slaves.
+     * Called when collar ownership changes.
+     */
+    public static void updateSlaves(Set<UUID> toAdd, Set<UUID> toRemove) {
+        ownedSlaves.removeAll(toRemove);
+        ownedSlaves.addAll(toAdd);
+    }
+
+    /**
+     * Add a single slave to the cache.
+     */
+    public static void addSlave(UUID slaveUUID) {
+        ownedSlaves.add(slaveUUID);
+    }
+
+    /**
+     * Remove a single slave from the cache.
+     */
+    public static void removeSlave(UUID slaveUUID) {
+        ownedSlaves.remove(slaveUUID);
+    }
+
+    /**
+     * Clear all slaves from the cache.
+     * Called on logout or dimension change.
+     */
+    public static void clear() {
+        ownedSlaves.clear();
+    }
+
+    // ==================== QUERIES ====================
+
+    /**
+     * Get all slave UUIDs owned by the local player.
+     * Returns an unmodifiable view.
+     */
+    public static Set<UUID> getSlaves() {
+        return Collections.unmodifiableSet(ownedSlaves);
+    }
+
+    /**
+     * Check if the local player owns a specific slave.
+     */
+    public static boolean ownsSlave(UUID slaveUUID) {
+        return ownedSlaves.contains(slaveUUID);
+    }
+
+    /**
+     * Get the number of slaves owned by the local player.
+     */
+    public static int getSlaveCount() {
+        return ownedSlaves.size();
+    }
+
+    /**
+     * Check if the local player has any slaves.
+     */
+    public static boolean hasSlaves() {
+        return !ownedSlaves.isEmpty();
+    }
+}