docs: 修正 API 文档准确性 (第四轮检查)

修复问题:
- containers: HashMap 实现描述修正
- debug: XE_LOG 宏参数顺序修正
- memory: ProxyAllocator 统计示例修正, PoolAllocator allocate size 检查描述
- resources: ResourceManager 缺失 UnloadGroup 方法
- rhi: D3D12 格式枚举名称修正, Texture Format 枚举补全, ResourceStates 补充
- threading: TaskGroup GetProgress/Wait/Cancel 实现限制说明

docs/api/memory/proxy-allocator/get-stats.md

@@ -27,12 +27,12 @@ proxy.Free(proxy.Allocate(256));
 
 const ProxyAllocator::Stats& stats = proxy.GetStats();
 printf("Total allocated: %zu bytes\n", stats.totalAllocated);
-printf("Total freed: %zu bytes\n", stats.totalFreed);
+printf("Total freed: %zu times\n", stats.totalFreed);
 printf("Peak allocated: %zu bytes\n", stats.peakAllocated);
 printf("Allocation count: %zu\n", stats.allocationCount);
 printf("Memory overhead: %zu bytes\n", stats.memoryOverhead);
 printf("Current in use: %zu bytes\n",
-    stats.totalAllocated - stats.totalFreed);
+    stats.totalAllocated - stats.allocationCount * sizeof(/* typical block */ size_t));
 ```
 
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