feat: implement hardcore hearts with game mode lock

Display hardcore heart textures when a world is in hardcore mode,
matching Java Edition behavior. Hearts switch between normal/hardcore
across all states (poison, wither, flash) and all HUD resolutions.

C++ changes:
- IUIScene_HUD: check isHardcore() and call SetHardcoreMode() each tick
- UIScene_HUD: send hardcore boolean to Flash via Iggy, invalidate
  SetHealth dirty check on state change to force heart redraw
- CreateWorldMenu/LoadMenu: lock game mode to Survival when hardcore
- MinecraftServer: gate server.properties hardcore override behind
  MINECRAFT_SERVER_BUILD so offline worlds preserve their saved flag

SWF changes (via new Java tools):
- AddHardcoreBitmaps: adds 10 hardcore heart bitmaps to graphics SWFs
- AddHardcoreHearts: adds 10 new frames (15-24) to health sprite
- PatchHudABC: patches HUD ActionScript bytecode with SetHardcore
  method and frame offset logic (+14 normal/poison, +6 wither)

Also updates README changelog styling with consistent ### headings.

tools/DecompileAS.java

@@ -0,0 +1,106 @@
+import com.jpexs.decompiler.flash.SWF;
+import com.jpexs.decompiler.flash.tags.*;
+import com.jpexs.decompiler.flash.abc.*;
+import com.jpexs.decompiler.flash.abc.avm2.AVM2ConstantPool;
+import com.jpexs.decompiler.flash.abc.types.*;
+import com.jpexs.decompiler.flash.abc.types.traits.*;
+import java.io.*;
+import java.util.*;
+
+/**
+ * Decompiles ActionScript 3 class/method signatures from a SWF.
+ * Usage: DecompileAS <swf-file>
+ */
+public class DecompileAS {
+    public static void main(String[] args) throws Exception {
+        if (args.length < 1) {
+            System.out.println("Usage: DecompileAS <swf-file>");
+            return;
+        }
+
+        SWF swf = new SWF(new FileInputStream(args[0]), false);
+
+        for (Tag tag : swf.getTags()) {
+            if (tag instanceof ImportAssets2Tag) {
+                ImportAssets2Tag imp = (ImportAssets2Tag) tag;
+                System.out.println("=== ImportAssets2 ===");
+                System.out.println("  URL: " + imp.url);
+            }
+
+            if (tag instanceof DoABC2Tag) {
+                DoABC2Tag abcTag = (DoABC2Tag) tag;
+                ABC abc = abcTag.getABC();
+                AVM2ConstantPool cp = abc.constants;
+
+                System.out.println("=== ABC: " + abcTag.name + " ===");
+                System.out.println("Classes: " + abc.instance_info.size());
+                System.out.println();
+
+                for (int c = 0; c < abc.instance_info.size(); c++) {
+                    InstanceInfo ii = abc.instance_info.get(c);
+                    System.out.println("--- Class: " + resolveName(cp, ii.name_index) + " ---");
+                    if (ii.super_index > 0)
+                        System.out.println("  extends " + resolveName(cp, ii.super_index));
+
+                    for (Trait t : ii.instance_traits.traits) {
+                        dumpTrait(abc, cp, t, "  ");
+                    }
+
+                    ClassInfo ci = abc.class_info.get(c);
+                    for (Trait t : ci.static_traits.traits) {
+                        System.out.print("  [static] ");
+                        dumpTrait(abc, cp, t, "");
+                    }
+                    System.out.println();
+                }
+            }
+        }
+    }
+
+    static String resolveName(AVM2ConstantPool cp, int multinameIdx) {
+        if (multinameIdx <= 0) return "*";
+        Multiname mn = cp.getMultiname(multinameIdx);
+        String name = mn.name_index > 0 ? cp.getString(mn.name_index) : "?";
+        int nsIdx = mn.namespace_index;
+        if (nsIdx > 0) {
+            Namespace ns = cp.getNamespace(nsIdx);
+            String nsName = ns.name_index > 0 ? cp.getString(ns.name_index) : "";
+            if (!nsName.isEmpty()) return nsName + "." + name;
+        }
+        return name;
+    }
+
+    static void dumpTrait(ABC abc, AVM2ConstantPool cp, Trait t, String indent) {
+        try {
+            String name = resolveName(cp, t.name_index);
+
+            if (t instanceof TraitMethodGetterSetter) {
+                TraitMethodGetterSetter tm = (TraitMethodGetterSetter) t;
+                MethodInfo mi = abc.method_info.get(tm.method_info);
+
+                String kind = tm.kindType == Trait.TRAIT_GETTER ? "get" :
+                              tm.kindType == Trait.TRAIT_SETTER ? "set" : "function";
+
+                StringBuilder sig = new StringBuilder();
+                sig.append(kind).append(" ").append(name).append("(");
+                for (int p = 0; p < mi.param_types.length; p++) {
+                    if (p > 0) sig.append(", ");
+                    sig.append(resolveName(cp, mi.param_types[p]));
+                }
+                sig.append(")");
+                sig.append(" : ").append(resolveName(cp, mi.ret_type));
+
+                System.out.println(indent + sig);
+            } else if (t instanceof TraitSlotConst) {
+                TraitSlotConst ts = (TraitSlotConst) t;
+                String type = resolveName(cp, ts.type_index);
+                String constKind = ts.kindType == Trait.TRAIT_CONST ? "const" : "var";
+                System.out.println(indent + constKind + " " + name + " : " + type);
+            } else if (t instanceof TraitClass) {
+                System.out.println(indent + "[class] " + name);
+            }
+        } catch (Exception e) {
+            System.out.println(indent + "[error: " + e.getMessage() + "]");
+        }
+    }
+}