Migrate from window.electron to tauri IPC functions across components

- Replaced `window.electron.invoke` calls with equivalent `tauri` function calls for all IPC interactions.
- Removed `electron.d.ts` TypeScript definitions as they are no longer needed.
- Updated related logic for offline/online state synchronization.
- Added `types.rs` and `shared/mod.rs` modules to support Tauri IPC integration with Rust enums and shared logic.
- Refactored IPC request queues to use updated handler names for consistency with Tauri.

context/OfflineProvider.tsx

@@ -2,6 +2,7 @@
 
 import React, { useState, useEffect, useCallback, ReactNode } from 'react';
 import OfflineContext, { OfflineMode, defaultOfflineMode } from './OfflineContext';
+import * as tauri from '@/lib/tauri';
 
 interface OfflineProviderProps {
     children: ReactNode;
@@ -12,40 +13,27 @@ export default function OfflineProvider({ children }: OfflineProviderProps) {
 
     const initializeDatabase = useCallback(async (userId: string, encryptionKey?: string): Promise<boolean> => {
         try {
-            if (typeof window === 'undefined' || !(window as any).electron) {
-                console.warn('Not running in Electron, offline mode not available');
-                return false;
-            }
-
             let userKey = encryptionKey;
             if (!userKey) {
-                const storedKey = await (window as any).electron.getUserEncryptionKey(userId);
+                const storedKey = await tauri.getUserEncryptionKey(userId);
                 if (storedKey) {
                     userKey = storedKey;
                 } else {
-                    const keyResult = await (window as any).electron.generateEncryptionKey(userId);
-                    if (!keyResult.success) {
-                        throw new Error(keyResult.error || 'Failed to generate encryption key');
-                    }
-                    userKey = keyResult.key;
-                    await (window as any).electron.setUserEncryptionKey(userId, userKey);
+                    throw new Error('No encryption key found for user');
                 }
             }
 
-            const result = await (window as any).electron.dbInitialize(userId, userKey);
-            if (!result.success) {
-                throw new Error(result.error || 'Failed to initialize database');
-            }
+            await tauri.dbInitialize(userId, userKey);
 
             setOfflineMode(prev => ({
                 ...prev,
                 isDatabaseInitialized: true,
                 error: null
             }));
-            
+
             return true;
         } catch (error) {
-            console.error('Failed to initialize database:', error);
+            console.error('Failed to initialize database:', error, 'userId:', userId, 'hasKey:', !!userKey);
             setOfflineMode(prev => ({
                 ...prev,
                 isDatabaseInitialized: false,