feat(rpc): migrate base_subscribe to eth_subscribe

[madisoncarter1234]

Summary

Migrates flashblocks subscriptions from the base namespace to the eth namespace per #250.

Since no release has been cut with base_subscribe yet, this is a clean replacement with no backwards compatibility needed.

• Rename BasePubSubApi → EthPubSubApi (namespace: base → eth)
• Rename BasePubSub → EthPubSub
• Rename BaseSubscriptionKind → EthSubscriptionKind
• Use replace_configured to override reth's existing eth_subscribe
• Update all tests to use eth_subscribe/eth_unsubscribe

Usage

- method: "base_subscribe", params: ["newFlashblocks"]
+ method: "eth_subscribe", params: ["newFlashblocks"]

- method: "base_unsubscribe"
+ method: "eth_unsubscribe"

Test plan

• All 18 flashblocks RPC tests pass
• Release build succeeds

Closes #250

[cb-heimdall]

✅ Heimdall Review Status

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[refcell]

This looks good to me. Would appreciate second set of eyes from @danyalprout. Since we're using replace_configured on the module context, we shouldn't run into any namespace collision errors and the test suite should validate this behavior. Nice work @madisoncarter1234!

[madisoncarter1234]

This looks good to me. Would appreciate second set of eyes from @danyalprout. Since we're using replace_configured on the module context, we shouldn't run into any namespace collision errors and the test suite should validate this behavior. Nice work @madisoncarter1234!

glad to help!!