FRE-600: Fix code review blockers

- Consolidated duplicate UndoManagers to single instance
- Fixed connection promise to only resolve on 'connected' status
- Fixed WebSocketProvider import (WebsocketProvider)
- Added proper doc.destroy() cleanup
- Renamed isPresenceInitialized property to avoid conflict

Co-Authored-By: Paperclip <noreply@paperclip.ing>

node_modules/viem/chains/definitions/merlinErigonTestnet.ts

@@ -0,0 +1,22 @@
+import { defineChain } from '../../utils/chain/defineChain.js'
+
+export const merlinErigonTestnet = /*#__PURE__*/ defineChain({
+  id: 4203,
+  name: 'Merlin Erigon Testnet',
+  nativeCurrency: {
+    name: 'BTC',
+    symbol: 'BTC',
+    decimals: 18,
+  },
+  rpcUrls: {
+    default: { http: ['https://testnet-erigon-rpc.merlinchain.io'] },
+  },
+  blockExplorers: {
+    default: {
+      name: 'blockscout',
+      url: 'https://testnet-erigon-scan.merlinchain.io',
+      apiUrl: 'https://testnet-erigon-scan.merlinchain.io/api',
+    },
+  },
+  testnet: true,
+})