feat: add fields l1_rpc_client and l2_rpc_client to SingleChainHost

[kien-rise]

Resolves #3048

These changes are required to introduce throttling and retry logic to handle timeouts and 429 (Too Many Requests) errors from the L1 RPC.

[codecov]

Codecov Report

❌ Patch coverage is 0% with 18 lines in your changes missing coverage. Please review.
✅ Project coverage is 77.0%. Comparing base (fe6dfcf) to head (52ff7c2).
✅ All tests successful. No failed tests found.

Files with missing lines	Patch %	Lines
bin/host/src/single/cfg.rs	0.0%	18 Missing ⚠️

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HEAD has 23 uploads less than BASE

Flag	BASE (fe6dfcf)	HEAD (52ff7c2)
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e2e	11	0
unit	2	1

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[theochap]

Ideally we wouldn't want to return an error in that case. Instead, can we enforce that the config specifies either an l1 rpc client or an l1 node address (by using an enum)?

[kien-rise]

/// The host binary CLI application arguments.
#[derive(Default, Parser, Serialize, Clone, Debug)]
#[command(styles = cli_styles())]
pub struct SingleChainHost {

How about we remove #[derive(Serialize)] and then apply the following change?

Before

    /// Address of L1 JSON-RPC endpoint to use (eth and debug namespace required)
    #[arg(
        long,
        visible_alias = "l1",
        requires = "l2_node_address",
        requires = "l1_beacon_address",
        env
    )]
    pub l1_node_address: Option<String>,
    /// Pre-configured L1 RPC client (not settable via CLI, used internally)
    #[serde(skip)]
    #[arg(skip)]
    pub l1_rpc_client: Option<RpcClient>,

After

    #[arg(
        long,
        aliases = ["l1", "l1_node_address"]
        visible_alias = "l1",
        requires = "l2_node_address",
        requires = "l1_beacon_address",
        value_parser = parse_rpc_client,
        env
    )]
    pub l1_rpc: RpcClient,


fn parse_rpc_client(s: &str) -> Result<RpcClient, String> {
  todo!()
}

[theochap]

Looks good! Let me know when it's done

[kien-rise]

Here’s my draft commit: kien-rise@ab470c6

I’ll test it, and once it’s confirmed to work, I’ll update this PR accordingly.

[theochap]

Same here