refactor: 消除冗余、统一设计，bump 0.9.1

- 提取 EntryRow/SecretFieldRow 到 models.rs
- 提取 current_actor()、print_json() 公共函数
- ExportFormat::from_extension 复用 from_str
- fetch_entries 默认 limit 100k（export/inject/run 不再截断）
- history 独立为 history.rs 模块
- delete 改用 DeleteArgs 结构体
- config_dir 改为 Result，Argon2id 参数提取常量
- Cargo 依赖 ^ 前缀、tokio 精简 features
- 更新 AGENTS.md 项目结构

Made-with: Cursor

src/commands/config.rs

@@ -15,7 +15,7 @@ pub async fn run(action: crate::ConfigAction) -> Result<()> {
                 database_url: Some(url.clone()),
             };
             config::save_config(&cfg)?;
-            println!("Database URL saved to: {}", config_path().display());
+            println!("Database URL saved to: {}", config_path()?.display());
             println!("  {}", mask_password(&url));
         }
         crate::ConfigAction::Show => {
@@ -23,7 +23,7 @@ pub async fn run(action: crate::ConfigAction) -> Result<()> {
             match cfg.database_url {
                 Some(url) => {
                     println!("database_url = {}", mask_password(&url));
-                    println!("config file:  {}", config_path().display());
+                    println!("config file:  {}", config_path()?.display());
                 }
                 None => {
                     println!("Database URL not configured.");
@@ -32,7 +32,7 @@ pub async fn run(action: crate::ConfigAction) -> Result<()> {
             }
         }
         crate::ConfigAction::Path => {
-            println!("{}", config_path().display());
+            println!("{}", config_path()?.display());
         }
     }
     Ok(())