test: migrate tests to SQLite database architecture

This commit refactors all tests to work with the new database-based
architecture, replacing the previous JSON config approach.

Key changes:
- Add Database export to lib.rs for test access
- Create test helper functions in support.rs:
  - create_test_state(): Creates empty test state with fresh DB
  - create_test_state_with_config(): Migrates JSON config to DB
- Fix environment isolation in provider_service tests:
  - provider_service_switch_missing_provider_returns_error
  - provider_service_switch_codex_missing_auth_returns_error
- Replace ignored export tests with working alternatives:
  - export_sql_writes_to_target_path (tests Database::export_sql)
  - export_sql_returns_error_for_invalid_path (tests error handling)
- Update error type matching to align with current implementation

All tests now:
- Use isolated test environments (test_mutex + reset_test_fs)
- Access data via Database API instead of RwLock<MultiAppConfig>
- Work with SQLite persistence layer
- Pass without environment pollution or race conditions

Fixes test compilation errors after database migration.

src-tauri/tests/mcp_commands.rs

@@ -1,15 +1,16 @@
-use std::{collections::HashMap, fs, sync::RwLock};
+use std::collections::HashMap;
+use std::fs;
 
 use serde_json::json;
 
 use cc_switch_lib::{
     get_claude_mcp_path, get_claude_settings_path, import_default_config_test_hook, AppError,
-    AppState, AppType, McpApps, McpServer, McpService, MultiAppConfig,
+    AppType, McpApps, McpServer, McpService, MultiAppConfig,
 };
 
 #[path = "support.rs"]
 mod support;
-use support::{ensure_test_home, reset_test_fs, test_mutex};
+use support::{create_test_state_with_config, ensure_test_home, reset_test_fs, test_mutex};
 
 #[test]
 fn import_default_config_claude_persists_provider() {
@@ -35,25 +36,22 @@ fn import_default_config_claude_persists_provider() {
 
     let mut config = MultiAppConfig::default();
     config.ensure_app(&AppType::Claude);
-    let state = AppState {
-        config: RwLock::new(config),
-    };
+    let state = create_test_state_with_config(&config).expect("create test state");
 
     import_default_config_test_hook(&state, AppType::Claude)
         .expect("import default config succeeds");
 
     // 验证内存状态
-    let guard = state.config.read().expect("lock config");
-    let manager = guard
-        .get_manager(&AppType::Claude)
-        .expect("claude manager present");
-    assert_eq!(manager.current, "default");
-    let default_provider = manager.providers.get("default").expect("default provider");
+    let providers = state.db.get_all_providers(AppType::Claude.as_str())
+        .expect("get all providers");
+    let current_id = state.db.get_current_provider(AppType::Claude.as_str())
+        .expect("get current provider");
+    assert_eq!(current_id.as_deref(), Some("default"));
+    let default_provider = providers.get("default").expect("default provider");
     assert_eq!(
         default_provider.settings_config, settings,
         "default provider should capture live settings"
     );
-    drop(guard);
 
     // 验证配置已持久化
     let config_path = home.join(".cc-switch").join("config.json");
@@ -65,13 +63,13 @@ fn import_default_config_claude_persists_provider() {
 
 #[test]
 fn import_default_config_without_live_file_returns_error() {
+    use support::create_test_state;
+
     let _guard = test_mutex().lock().expect("acquire test mutex");
     reset_test_fs();
     let home = ensure_test_home();
 
-    let state = AppState {
-        config: RwLock::new(MultiAppConfig::default()),
-    };
+    let state = create_test_state().expect("create test state");
 
     let err = import_default_config_test_hook(&state, AppType::Claude)
         .expect_err("missing live file should error");
@@ -115,9 +113,8 @@ fn import_mcp_from_claude_creates_config_and_enables_servers() {
     )
     .expect("seed ~/.claude.json");
 
-    let state = AppState {
-        config: RwLock::new(MultiAppConfig::default()),
-    };
+    let config = MultiAppConfig::default();
+    let state = create_test_state_with_config(&config).expect("create test state");
 
     let changed = McpService::import_from_claude(&state).expect("import mcp from claude succeeds");
     assert!(
@@ -125,13 +122,8 @@ fn import_mcp_from_claude_creates_config_and_enables_servers() {
         "import should report inserted or normalized entries"
     );
 
-    let guard = state.config.read().expect("lock config");
-    // v3.7.0: 检查统一结构
-    let servers = guard
-        .mcp
-        .servers
-        .as_ref()
-        .expect("unified servers should exist");
+    let servers = state.db.get_all_mcp_servers()
+        .expect("get all mcp servers");
     let entry = servers
         .get("echo")
         .expect("server imported into unified structure");
@@ -139,7 +131,6 @@ fn import_mcp_from_claude_creates_config_and_enables_servers() {
         entry.apps.claude,
         "imported server should have Claude app enabled"
     );
-    drop(guard);
 
     let config_path = home.join(".cc-switch").join("config.json");
     assert!(
@@ -150,6 +141,8 @@ fn import_mcp_from_claude_creates_config_and_enables_servers() {
 
 #[test]
 fn import_mcp_from_claude_invalid_json_preserves_state() {
+    use support::create_test_state;
+
     let _guard = test_mutex().lock().expect("acquire test mutex");
     reset_test_fs();
     let home = ensure_test_home();
@@ -158,9 +151,7 @@ fn import_mcp_from_claude_invalid_json_preserves_state() {
     fs::write(&mcp_path, "{\"mcpServers\":") // 不完整 JSON
         .expect("seed invalid ~/.claude.json");
 
-    let state = AppState {
-        config: RwLock::new(MultiAppConfig::default()),
-    };
+    let state = create_test_state().expect("create test state");
 
     let err =
         McpService::import_from_claude(&state).expect_err("invalid json should bubble up error");
@@ -221,27 +212,21 @@ fn set_mcp_enabled_for_codex_writes_live_config() {
         },
     );
 
-    let state = AppState {
-        config: RwLock::new(config),
-    };
+    let state = create_test_state_with_config(&config).expect("create test state");
 
     // v3.7.0: 使用 toggle_app 替代 set_enabled
     McpService::toggle_app(&state, "codex-server", AppType::Codex, true)
         .expect("toggle_app should succeed");
 
-    let guard = state.config.read().expect("lock config");
-    let entry = guard
-        .mcp
-        .servers
-        .as_ref()
-        .unwrap()
+    let servers = state.db.get_all_mcp_servers()
+        .expect("get all mcp servers");
+    let entry = servers
         .get("codex-server")
         .expect("codex server exists");
     assert!(
         entry.apps.codex,
         "server should have Codex app enabled after toggle"
     );
-    drop(guard);
 
     let toml_path = cc_switch_lib::get_codex_config_path();
     assert!(