fix: validate WC session covers all chains before reuse

[2wheeh]

Description

When a WalletConnect session already existed, connect() returned early without validating whether the session covered all required chains.

if (this.provider.session) {
  return Promise.resolve(); // no chain validation                                 
}

If the chain configuration changed after the initial connection (e.g., adding a new chain), the stale session didn't include the new chain's namespace, causing signing requests to fail.

Since the session was never disconnected, subsequent reconnect attempts kept reusing the same stale session, locking the wallet into an error state.

Changes

• Compute the required chain list (cosmos/eip155/solana) before checking the session
• Reuse the existing session only if its namespaces cover all required chains
• If any chain is missing, disconnect() the stale session and create a new one