feat: sync current providers to live files after config import

Core Improvements:
- Add sync_current_providers_live command to synchronize in-memory provider
  settings to corresponding live files (~/.claude/settings.json or ~/.codex/auth.json)
- Introduce partial-success state to distinguish between 'import succeeded
  but sync failed' scenario, providing clear user feedback
- Remove unused skip_live_backfill parameter from switch_provider command
- Separate responsibilities: backend handles import/backup, frontend handles
  sync/error presentation

Technical Details:
- Codex: sync auth.json + config.toml with MCP configuration
- Claude: sync settings.json
- Bidirectional sync: read back after write to update in-memory settings_config
- Full i18n support (English and Chinese)
- Graceful handling when no current provider is active

Affected Files:
- Backend: import_export.rs, commands.rs, lib.rs
- Frontend: useImportExport.ts, ImportExportSection.tsx, settings.ts
- i18n: en.json, zh.json

This ensures SSOT (Single Source of Truth) consistency between config.json
and live configuration files after import operations.

src-tauri/src/import_export.rs

@@ -1,3 +1,5 @@
+use crate::app_config::{AppType, MultiAppConfig};
+use crate::provider::Provider;
 use chrono::Utc;
 use serde_json::{json, Value};
 use std::fs;
@@ -79,6 +81,113 @@ fn cleanup_old_backups(backup_dir: &PathBuf, retain: usize) -> Result<(), String
     Ok(())
 }
 
+fn sync_current_providers_to_live(config: &mut MultiAppConfig) -> Result<(), String> {
+    sync_current_provider_for_app(config, &AppType::Claude)?;
+    sync_current_provider_for_app(config, &AppType::Codex)?;
+    Ok(())
+}
+
+fn sync_current_provider_for_app(
+    config: &mut MultiAppConfig,
+    app_type: &AppType,
+) -> Result<(), String> {
+    let (current_id, provider) = {
+        let manager = match config.get_manager(app_type) {
+            Some(manager) => manager,
+            None => return Ok(()),
+        };
+
+        if manager.current.is_empty() {
+            return Ok(());
+        }
+
+        let current_id = manager.current.clone();
+        let provider = match manager.providers.get(&current_id) {
+            Some(provider) => provider.clone(),
+            None => {
+                log::warn!(
+                    "当前应用 {:?} 的供应商 {} 不存在，跳过 live 同步",
+                    app_type,
+                    current_id
+                );
+                return Ok(());
+            }
+        };
+        (current_id, provider)
+    };
+
+    match app_type {
+        AppType::Codex => sync_codex_live(config, &current_id, &provider)?,
+        AppType::Claude => sync_claude_live(config, &current_id, &provider)?,
+    }
+
+    Ok(())
+}
+
+fn sync_codex_live(
+    config: &mut MultiAppConfig,
+    provider_id: &str,
+    provider: &Provider,
+) -> Result<(), String> {
+    use serde_json::Value;
+
+    let settings = provider
+        .settings_config
+        .as_object()
+        .ok_or_else(|| format!("供应商 {} 的 Codex 配置必须是对象", provider_id))?;
+    let auth = settings
+        .get("auth")
+        .ok_or_else(|| format!("供应商 {} 的 Codex 配置缺少 auth 字段", provider_id))?;
+    if !auth.is_object() {
+        return Err(format!(
+            "供应商 {} 的 Codex auth 配置必须是 JSON 对象",
+            provider_id
+        ));
+    }
+    let cfg_text = settings.get("config").and_then(Value::as_str);
+
+    crate::codex_config::write_codex_live_atomic(auth, cfg_text)?;
+    crate::mcp::sync_enabled_to_codex(config)?;
+
+    let cfg_text_after = crate::codex_config::read_and_validate_codex_config_text()?;
+    if let Some(manager) = config.get_manager_mut(&AppType::Codex) {
+        if let Some(target) = manager.providers.get_mut(provider_id) {
+            if let Some(obj) = target.settings_config.as_object_mut() {
+                obj.insert(
+                    "config".to_string(),
+                    serde_json::Value::String(cfg_text_after),
+                );
+            }
+        }
+    }
+
+    Ok(())
+}
+
+fn sync_claude_live(
+    config: &mut MultiAppConfig,
+    provider_id: &str,
+    provider: &Provider,
+) -> Result<(), String> {
+    use crate::config::{read_json_file, write_json_file};
+
+    let settings_path = crate::config::get_claude_settings_path();
+    if let Some(parent) = settings_path.parent() {
+        std::fs::create_dir_all(parent).map_err(|e| format!("创建 Claude 配置目录失败: {}", e))?;
+    }
+
+    write_json_file(&settings_path, &provider.settings_config)?;
+
+    let live_after = read_json_file::<serde_json::Value>(&settings_path)?;
+    if let Some(manager) = config.get_manager_mut(&AppType::Claude) {
+        if let Some(target) = manager.providers.get_mut(provider_id) {
+            target.settings_config = live_after;
+        }
+    }
+
+    Ok(())
+}
+
 /// 导出配置文件
 #[tauri::command]
 pub async fn export_config_to_file(file_path: String) -> Result<Value, String> {
@@ -135,6 +244,25 @@ pub async fn import_config_from_file(
     }))
 }
 
+/// 同步当前供应商配置到对应的 live 文件
+#[tauri::command]
+pub async fn sync_current_providers_live(
+    state: tauri::State<'_, crate::store::AppState>,
+) -> Result<Value, String> {
+    {
+        let mut config_state = state
+            .config
+            .lock()
+            .map_err(|e| format!("Failed to lock config: {}", e))?;
+        sync_current_providers_to_live(&mut config_state)?;
+    }
+
+    Ok(json!({
+        "success": true,
+        "message": "Live configuration synchronized"
+    }))
+}
+
 /// 保存文件对话框
 #[tauri::command]
 pub async fn save_file_dialog<R: tauri::Runtime>(