Implement password verification and enhance BackupScreen UI

- Added password verification logic in MainActivity to decrypt the private key and seed phrase.
- Updated BackupScreen to handle password verification asynchronously using coroutines.
- Improved UI layout for displaying seed phrases in two columns with colored words.
- Added a copy button for the seed phrase with clipboard functionality.
- Introduced a new composable function, WordItem, for better visual representation of seed phrase words.

app/src/main/java/com/rosetta/messenger/MainActivity.kt

@@ -542,10 +542,35 @@ fun MainScreen(
                         showSafetyScreen = true
                     },
                     onVerifyPassword = { password ->
-                        // TODO: Implement password verification
-                        if (password == "test") {
-                            "word1 word2 word3 word4 word5 word6 word7 word8 word9 word10 word11 word12"
-                        } else null
+                        // Verify password by trying to decrypt the private key
+                        try {
+                            val publicKey = account?.publicKey ?: return@BackupScreen null
+                            val accountManager = AccountManager(context)
+                            val encryptedAccount = accountManager.getAccount(publicKey)
+                            
+                            if (encryptedAccount != null) {
+                                // Try to decrypt private key with password
+                                val decryptedPrivateKey = com.rosetta.messenger.crypto.CryptoManager.decryptWithPassword(
+                                    encryptedAccount.encryptedPrivateKey,
+                                    password
+                                )
+                                
+                                if (decryptedPrivateKey != null) {
+                                    // Password is correct, decrypt seed phrase
+                                    com.rosetta.messenger.crypto.CryptoManager.decryptWithPassword(
+                                        encryptedAccount.encryptedSeedPhrase,
+                                        password
+                                    )
+                                } else {
+                                    null
+                                }
+                            } else {
+                                null
+                            }
+                        } catch (e: Exception) {
+                            Log.e("MainActivity", "Error verifying password", e)
+                            null
+                        }
                     }
                 )
             }