docs: 修正全部文档使其与源码实现一致

- Plugin.Start(sdk *PluginSDK) 接口签名改为指针
- 方法表重写: 移除 CallLLM/QueryKnowledge/SetMemory 等不存在方法
- IOInjector 参数顺序修正为 (source, channel, text)
- 删除虚构 SDKConfig, 替换为实际 New() 构造函数签名
- .hmap 内容描述一致化 (plugin.so + plugin.dll + main.lua)
- 添加 meta/ 包元数据文件

tools/plugindev/templates/plg.json.tmpl

@@ -0,0 +1,11 @@
+{
+  "name": "{{.Plg.Name}}",
+  "name_zh": "{{.Plg.NameZh}}",
+  "name_en": "{{.Plg.NameEn}}",
+  "version": "{{.Plg.Version}}",
+  "description": "{{.Plg.Description}}",
+  "author": "{{.Plg.Author}}",
+  "entry": "{{.Plg.Entry}}",
+  "tags": {{.Plg.Tags}},
+  "targets": "{{.Plg.Targets}}"
+}