refactor: restructure storage and environment modules; remove unused code

- Deleted unused PouchDB configuration and types from core storage.
- Removed Electron-related hooks and utilities that are no longer needed.
- Introduced new local storage management for application keys.
- Created a new environment wrapper for landing application.
- Added public HTTP client for landing application with minimal configuration.
- Implemented new PouchDB entities for items and POS configurations.
- Updated main application entry point to reflect new storage structure.

apps/web/src/core/hooks/use-electron-updater.ts

@@ -0,0 +1,140 @@
+import { useState, useEffect, useCallback } from 'react';
+import { useIsElectron } from './use-is-electron';
+
+// ─── Types ──────────────────────────────────────────────────────
+
+export type UpdateStatus =
+  | 'idle'
+  | 'checking'
+  | 'available'
+  | 'not-available'
+  | 'downloading'
+  | 'ready'
+  | 'error';
+
+export interface UseElectronUpdaterReturn {
+  /** Current status of the auto-updater lifecycle */
+  status: UpdateStatus;
+  /** Download progress percentage (0–100) */
+  progress: number;
+  /** Download speed in bytes per second */
+  bytesPerSecond: number;
+  /** Information about the available/downloaded update */
+  updateInfo: ElectronUpdateInfo | null;
+  /** Error message if the updater encountered an issue */
+  errorMessage: string | null;
+  /** Whether the app is running inside Electron */
+  isElectron: boolean;
+  /** Trigger a manual update check */
+  checkForUpdates: () => void;
+  /** Quit the app and install the downloaded update */
+  installUpdate: () => void;
+}
+
+/**
+ * React hook for the Electron auto-updater.
+ *
+ * Subscribes to all update lifecycle events via `window.electronAPI`
+ * and provides reactive state for building an update notification UI.
+ *
+ * Safe to use in both Electron and browser environments — all
+ * Electron-specific calls are gated behind `window.electronAPI` checks.
+ *
+ * @example
+ * ```tsx
+ * function UpdateBanner() {
+ *   const { status, progress, updateInfo, checkForUpdates, installUpdate } = useElectronUpdater();
+ *
+ *   if (status === 'available') {
+ *     return <div>Update {updateInfo?.version} available! Downloading...</div>;
+ *   }
+ *   if (status === 'downloading') {
+ *     return <div>Downloading... {progress.toFixed(0)}%</div>;
+ *   }
+ *   if (status === 'ready') {
+ *     return <button onClick={installUpdate}>Restart to update</button>;
+ *   }
+ *   return <button onClick={checkForUpdates}>Check for updates</button>;
+ * }
+ * ```
+ */
+export function useElectronUpdater(): UseElectronUpdaterReturn {
+  const [status, setStatus] = useState<UpdateStatus>('idle');
+  const [progress, setProgress] = useState(0);
+  const [bytesPerSecond, setBytesPerSecond] = useState(0);
+  const [updateInfo, setUpdateInfo] = useState<ElectronUpdateInfo | null>(null);
+  const [errorMessage, setErrorMessage] = useState<string | null>(null);
+
+  const isElectron = useIsElectron();
+
+  useEffect(() => {
+    if (!window.electronAPI) return;
+
+    const api = window.electronAPI;
+
+    const unsubChecking = api.onUpdateChecking(() => {
+      setStatus('checking');
+      setErrorMessage(null);
+    });
+
+    const unsubAvailable = api.onUpdateAvailable((info) => {
+      setStatus('available');
+      setUpdateInfo(info);
+    });
+
+    const unsubNotAvailable = api.onUpdateNotAvailable((info) => {
+      setStatus('not-available');
+      setUpdateInfo(info);
+    });
+
+    const unsubProgress = api.onDownloadProgress((progressInfo) => {
+      setStatus('downloading');
+      setProgress(progressInfo.percent);
+      setBytesPerSecond(progressInfo.bytesPerSecond);
+    });
+
+    const unsubDownloaded = api.onUpdateDownloaded((info) => {
+      setStatus('ready');
+      setProgress(100);
+      setUpdateInfo(info);
+    });
+
+    const unsubError = api.onUpdateError((error) => {
+      setStatus('error');
+      setErrorMessage(error);
+    });
+
+    // Cleanup all listeners on unmount
+    return () => {
+      unsubChecking();
+      unsubAvailable();
+      unsubNotAvailable();
+      unsubProgress();
+      unsubDownloaded();
+      unsubError();
+    };
+  }, []);
+
+  const checkForUpdates = useCallback(() => {
+    if (!window.electronAPI) return;
+    setStatus('checking');
+    setErrorMessage(null);
+    window.electronAPI.checkForUpdates();
+  }, []);
+
+  const installUpdate = useCallback(() => {
+    if (!window.electronAPI) return;
+    window.electronAPI.installUpdate();
+  }, []);
+
+  return {
+    status,
+    progress,
+    bytesPerSecond,
+    updateInfo,
+    errorMessage,
+    isElectron,
+    checkForUpdates,
+    installUpdate,
+  };
+}