fix(rhi): Fix RHI abstraction layer API docs per api-skill.md template

- Rename texture/dtor.md to destructor.md per template spec
- Remove duplicate non-hyphenated fence docs (getnativehandle.md, issignaled.md, getcompletedvalue.md)
- Fix template field issues:
  - swap-chain, command-queue: 类型 now uses 'class (abstract)'
  - sampler: 头文件 now uses full path 'XCEngine/RHI/RHISampler.h'
  - types: 类型 fixed from 'structs' to 'struct'
  - enums: 类型 fixed from 'enums' to 'enum class'
- Fix include paths in command-queue and pipeline-layout code examples
- Create missing constructor/destructor docs for 11 classes:
  buffer, texture, shader, device, command-list, command-queue,
  fence, sampler, swap-chain, pipeline-state, pipeline-layout
- Update class overview pages to include constructor/destructor entries

docs/api/rhi/buffer/buffer.md

@@ -16,6 +16,8 @@
 
 | 方法 | 描述 |
 |------|------|
+| [`RHIBuffer`](constructor.md) | 默认构造函数 |
+| [`~RHIBuffer`](destructor.md) | 虚析构函数 |
 | [`Map`](map.md) | 映射缓冲区到 CPU 可访问内存 |
 | [`Unmap`](unmap.md) | 取消映射 |
 | [`SetData`](set-data.md) | 设置缓冲区数据 |