diag(threadownership): 慢相位等待超2s时 dump 主线程+DR线程栈，抓死锁现场

背景：18:44 测试出现 tick 死锁——主线程在 custom payloads 相位的 managedBlock 里等
overworld 维度 loop 停(isTicking)，而 overworld 卡在 connections 阶段的
SableMainThreadBridge.runForLevel(server.execute排队 + completion.get 等主线程)，
tick 永不返回，单 tick 从 40s 单调涨到 203s。

ModernFix watchdog 的 Thread Dump 不含 Server thread/DR 线程，现场缺失。
本改动：ThreadOwnershipDiagnostics.slowPhase 等待 >2s 时 dumpKeyThreads()，
用 ThreadMXBean 输出 Server thread + 所有 dimensionalripper_* 线程的完整栈，
含 lockName/lockOwner/lockInfo/blocked/waited/ownedSynchronizers。
时间窗口 30s 限流，避免刷屏。纯诊断，不改执行逻辑。

src/main/java/dev/modzuozhi/core/compat/ThreadOwnershipDiagnostics.java

@@ -87,6 +87,42 @@ public final class ThreadOwnershipDiagnostics {
         long next = NEXT_SLOW_WARNING.get();
         if ((next == 0 || now - next >= 0) && NEXT_SLOW_WARNING.compareAndSet(next, now + TimeUnit.SECONDS.toNanos(30)))
             ModZuozhi.LOGGER.warn("[ThreadOwnership] {} waiting {} ms; {}", reason, (now-began)/1_000_000, report(server));
+        // 等待超过 2 秒：dump 主线程 + 所有 DR 线程栈，用于诊断死锁现场（每次慢相位最多一次）。
+        if (now - began >= TimeUnit.SECONDS.toNanos(2)) {
+            long nextDump = NEXT_DUMP.get();
+            if ((nextDump == 0 || now - nextDump >= 0)
+                    && NEXT_DUMP.compareAndSet(nextDump, now + TimeUnit.SECONDS.toNanos(30))) {
+                ModZuozhi.LOGGER.error("[ThreadOwnership] {} 等待超过 2s，dump 关键线程栈（诊断死锁）", reason);
+                dumpKeyThreads();
+            }
+        }
+    }
+
+    private static final AtomicLong NEXT_DUMP = new AtomicLong();
+
+    /** Dump Server thread + 所有 dimensionalripper_* 线程的完整栈（含锁信息），仅诊断用。 */
+    public static void dumpKeyThreads() {
+        try {
+            java.lang.management.ThreadMXBean mx = java.lang.management.ManagementFactory.getThreadMXBean();
+            for (java.lang.management.ThreadInfo info : mx.dumpAllThreads(true, true)) {
+                if (info == null) continue;
+                String name = info.getThreadName();
+                boolean key = name.equals("Server thread") || name.startsWith("dimensionalripper_");
+                if (!key) continue;
+                StringBuilder sb = new StringBuilder().append(name)
+                        .append(" #").append(info.getThreadId()).append(' ').append(info.getThreadState())
+                        .append(" lockName=").append(info.getLockName())
+                        .append(" lockOwner=").append(info.getLockOwnerName())
+                        .append(" lockInfo=").append(String.valueOf(info.getLockInfo()))
+                        .append(" blocked=").append(info.getBlockedCount())
+                        .append(" waited=").append(info.getWaitedCount());
+                for (StackTraceElement frame : info.getStackTrace()) sb.append("\n\tat ").append(frame);
+                for (var lock : info.getLockedSynchronizers()) sb.append("\n\towned: ").append(lock);
+                ModZuozhi.LOGGER.error("[ThreadOwnership dump] {}", sb);
+            }
+        } catch (RuntimeException failure) {
+            ModZuozhi.LOGGER.error("[ThreadOwnership] 线程栈 dump 失败", failure);
+        }
     }
 
     public static void phaseTiming(String reason, long began, long drained) {