fix(main): replace electron-store with native fs for ESM compatibility

- Remove electron-store dependency usage (ESM-only)
- Implement JSON file storage using native fs module
- Read/write config.json and secure.json directly
- Maintain same API for domain and version storage

.sisyphus/notepads/core-features/learnings.md

@@ -0,0 +1,57 @@
+# Learnings
+
+## [2026-03-12] Kintone Customize Manager Core Features
+
+### Technical Decisions
+
+1. **Type System Organization**
+   - Created separate type files for domain, kintone, version, and ipc types
+   - Used `Result<T>` pattern for unified IPC response handling
+   - Added path alias `@renderer/*` to tsconfig.node.json for main process imports
+
+2. **SafeStorage for Password Encryption**
+   - Used Electron's built-in `safeStorage` API instead of deprecated `keytar`
+   - Implemented `isSecureStorageAvailable()` check for Linux compatibility
+   - Store encrypted passwords as base64 strings in separate secure store
+
+3. **Kintone API Client**
+   - Used native `fetch` API (Node.js 18+) instead of axios
+   - Implemented 30-second timeout with AbortController
+   - Support both password authentication and API token authentication
+
+4. **IPC Architecture**
+   - All handlers return `{ success: boolean, data?: T, error?: string }`
+   - Used `contextBridge` to expose safe API to renderer
+   - Created typed `ElectronAPI` interface for window.api
+
+5. **State Management**
+   - Zustand with persist middleware for domain persistence
+   - Separate stores for domain, app, deploy, and version state
+   - IPC calls in store actions, not in components
+
+6. **UI Components**
+   - LobeHub UI + Ant Design 6 + antd-style for styling
+   - CodeMirror 6 for code viewing with syntax highlighting
+   - Step-by-step deploy dialog with confirmation
+
+### Gotchas
+
+1. **tsconfig.node.json needs @renderer/\* path alias**
+   - Main process files import from `@renderer/types`
+   - Without the alias, build fails
+
+2. **JSON import in preload requires named exports**
+   - Use `{ Component }` syntax, not `import Component from ...`
+   - Default exports don't work with contextBridge
+
+3. **CodeMirror extensions must match file type**
+   - Use `javascript()` for JS, `css()` for CSS files
+   - Extensions are loaded dynamically based on file type
+
+### Files Created
+
+- **Types**: domain.ts, kintone.ts, version.ts, ipc.ts
+- **Main**: storage.ts, kintone-api.ts, ipc-handlers.ts
+- **Preload**: index.ts, index.d.ts (updated)
+- **Stores**: domainStore.ts, appStore.ts, deployStore.ts, versionStore.ts
+- **Components**: DomainManager/, SpaceTree/, AppDetail/, CodeViewer/, FileUploader/, DeployDialog/, VersionHistory/