Add keepalive config to chain client

[fbac]

Add keepalive configuration to blockchain client initialization using functional options pattern

Refactors the blockchain.NewClient() constructor to use a functional options pattern with ClientOption parameters instead of directly accepting WebSocket URLs. The changes introduce new configuration functions WithWebSocketURL() and WithKeepAliveConfig() that allow configuring TCP keep-alive settings for WebSocket connections. The implementation adds a custom WebSocket dialer with configurable TCP keep-alive behavior, and updates all client initialization calls across the codebase to use the new pattern. In several locations, TCP keep-alive is explicitly disabled by setting Enable: false in the keep-alive configuration.

📍Where to Start

Start with the refactored NewClient function in client.go to understand the new functional options pattern and keep-alive configuration implementation.

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Macroscope summarized 180d8fe.

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[mkysel]

Can you give me the context? We are disabling it explicitly and enabling by default? Is this related to the restarts we see?

[fbac]

Can you give me the context? We are disabling it explicitly and enabling by default? Is this related to the restarts we see?

By default it's enabled, I'm only disabling these in short lived connections such as the cli retrieving some data.

In xmtpd it will use the default dialer, and in the indexer those values could be adjusted to the chain block times, etc.

And yep, this is relevant to the restarts we see. I'm not confident this is 100% the solution as I think these are related to the server (blockchain) mostly. In a followup PR I'm also including the backfill on sub recreation.