chore(secrets-mcp): 0.5.1 — 移除 entry type 归一化，MCP 参数兼容字符串形式

- 去掉 taxonomy 对 entry type 的自动映射与 metadata.subtype 回填；仅 trim 后入库
- MCP tools：Vec/Map/bool 等可选字段支持 JSON 内嵌字符串解析，并改进解析失败提示
- 新增 deser 单元测试；README/AGENTS 与 models 注释同步

Made-with: Cursor

crates/secrets-core/src/models.rs

@@ -4,7 +4,7 @@ use serde_json::Value;
 use std::collections::BTreeMap;
 use uuid::Uuid;
 
-/// A top-level entry (server, service, key, person, …).
+/// A top-level entry (server, service, account, person, …).
 /// Sensitive fields are stored separately in `secrets`.
 #[derive(Debug, Serialize, Deserialize, sqlx::FromRow)]
 pub struct Entry {