Fix rapid reconnect issue for shared clients

[chakra-guy]

This PR fixes a race condition issue for clients that use a shared client. The issue happened when the reconnect was called repeatedly on multiple clients over and over again as a group.

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Note

Implements idempotent reconnect() in SharedCentrifuge and updates WebSocketTransport to use it when sharing connections, with new unit/integration tests; minor demo tweaks.

• Core (WebSocket)
  • Add idempotent reconnect() to packages/core/src/transport/websocket/shared-centrifuge.ts using a shared reconnectPromise to prevent connection storms.
  • Update packages/core/src/transport/websocket/index.ts reconnect() to delegate to SharedCentrifuge.reconnect() when using shared connections; fallback for non-shared.
• Tests
  • Add unit tests shared-centrifuge.test.ts covering reconnect idempotency, concurrent/rapid calls, and edge cases.
  • Extend integration tests shared-centrifuge.integration.test.ts with scenarios for simultaneous and rapid reconnect cycles.
• Web Demo
  • Minor UI/template tweaks and updated hardcoded accounts in apps/web-demo/src/components/MetaMaskMobileDemo.tsx and Navigation.tsx.
  • Quote/style normalization in apps/web-demo/src/lib/encoding-utils.ts.

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