feat(tray): add Gemini support to system tray menu (#209)

Refactor tray menu system to support three applications (Claude/Codex/Gemini):
- Introduce generic TrayAppSection structure and TRAY_SECTIONS array
- Implement append_provider_section and handle_provider_tray_event helper functions
- Enhance Gemini provider service with .env config read/write support
- Implement Gemini LiveSnapshot for atomic operations and rollback
- Update README documentation to reflect Gemini tray quick switching feature

src-tauri/src/app_store.rs

@@ -56,9 +56,7 @@ fn read_override_from_store(app: &tauri::AppHandle) -> Option<PathBuf> {
             Some(path)
         }
         Some(_) => {
-            log::warn!(
-                "Store 中的 {STORE_KEY_APP_CONFIG_DIR} 类型不正确，应为字符串"
-            );
+            log::warn!("Store 中的 {STORE_KEY_APP_CONFIG_DIR} 类型不正确，应为字符串");
             None
         }
         None => None,