refactor(core): integrate SQLite database into application core

- Initialize database on app startup with migration from JSON config
- Update AppState to include Database instance alongside MultiAppConfig
- Simplify store module by removing unused session management code
- Add database initialization to app setup flow
- Support both database and legacy config during transition

src-tauri/src/store.rs

@@ -1,26 +1,14 @@
-use crate::app_config::MultiAppConfig;
-use crate::error::AppError;
-use std::sync::RwLock;
+use crate::database::Database;
+use std::sync::Arc;
 
 /// 全局应用状态
 pub struct AppState {
-    pub config: RwLock<MultiAppConfig>,
+    pub db: Arc<Database>,
 }
 
 impl AppState {
     /// 创建新的应用状态
-    /// 注意：仅在配置成功加载时返回；不会在失败时回退默认值。
-    pub fn try_new() -> Result<Self, AppError> {
-        let config = MultiAppConfig::load()?;
-        Ok(Self {
-            config: RwLock::new(config),
-        })
-    }
-
-    /// 保存配置到文件
-    pub fn save(&self) -> Result<(), AppError> {
-        let config = self.config.read().map_err(AppError::from)?;
-
-        config.save()
+    pub fn new(db: Arc<Database>) -> Self {
+        Self { db }
     }
 }