Harden test suite reliability for Anvil and WebSocket tests

[dominicletz]

Summary

• Retry RemoteChain.RPC.rpc/3 when NodeProxy returns {:error, :disconnect} instead of crashing with a CaseClauseError
• Bootstrap Anvil in tests via HTTP anvil_mine and restore selective ChainList.refresh_chains/1 cache updates
• Make PeerReadyEts tolerant of a missing ETS table during test service restarts
• Stabilize WebSocket E2E and billing tests with PubSub.publish, device isolation, and cleaner test resets

Test plan

• mix test — 187 passed, 6 skipped
• mix lint — passes (Credo + Dialyzer)

[gemini-code-assist]

Code Review

This pull request introduces several robustness improvements, including retry logic for RPC disconnects, dynamic initialization and checks for the PeerReady ETS table, and refactored chain list caching. It also updates test helpers and integration tests to ensure reliable execution. The review feedback highlights a potential race condition in the concurrent creation of the ETS table, suggests a more defensive fallback clause in the RPC retry logic to avoid CaseClauseError crashes, and recommends using the idiomatic is_nil/1 check in Elixir.

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[gemini-code-assist]

In a concurrent environment, multiple processes calling ensure/0 simultaneously (e.g., during concurrent connection setups) can cause a race condition where both see :undefined and attempt to create the named ETS table @table. This will result in an ArgumentError crash. Rescuing the ArgumentError ensures that concurrent calls to ensure/0 handle this race condition gracefully.

  def ensure do
    case :ets.info(@table) do
      :undefined ->
        try do
          :ets.new(@table, [:named_table, :set, :public, read_concurrency: true])
          :ok
        rescue
          ArgumentError -> :ok
        end

      _ ->
        :ok
    end
  end

[gemini-code-assist]

Using a generic {:error, reason} fallback clause instead of a specific {:error, :disconnect} clause when retries_left <= 0 makes the code more robust and defensive. If RemoteChain.NodeProxy.rpc/3 ever returns other error tuples in the future, this prevents a CaseClauseError crash and propagates the error gracefully.

      {:error, :disconnect} when retries_left > 0 ->
        Process.sleep(200)
        rpc_with_retry(chain, method, params, retries_left - 1)

      {:error, reason} ->
        {:error, reason}

[gemini-code-assist]

In Elixir, it is more idiomatic to use the is_nil/1 guard or not is_nil/1 instead of comparing directly with nil using != or == operators.

      if not only_cached? or not is_nil(Globals.get(key)) do