Support /finalized-stream in hotblocks DB

[kalabukdima]

If finalized head is not available in the snapshot, throws HTTP 500. Otherwise, streams data capped to the finalized head

[Copilot]

Pull Request Overview

This PR adds support for querying only finalized blocks by introducing a new /finalized-stream endpoint and corresponding query logic. This allows clients to request data only up to the finalized head, ensuring they don't receive potentially reorged blocks.

• Introduces new query_finalized public API method alongside the existing query method
• Adds wait_for_finalized_block method to track finalized block progression
• Implements finalized block capping logic to constrain queries within finalized boundaries

Reviewed Changes

Copilot reviewed 5 out of 5 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
crates/hotblocks/src/query/service.rs	Refactored query logic into internal method with finalized flag, added query_finalized public method
crates/hotblocks/src/query/running.rs	Added logic to cap query's last_block to finalized head when only_finalized is true
crates/hotblocks/src/query/response.rs	Threaded only_finalized parameter through to RunningQuery
crates/hotblocks/src/dataset_controller/dataset_controller.rs	Added wait_for_finalized_block method mirroring wait_for_block
crates/hotblocks/src/api.rs	Added /finalized-stream endpoint and refactored stream handlers to share internal implementation

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[Copilot]

[nitpick] The variable capped_last is unnecessary and reduces clarity. Directly return the result of the expression on line 102-105.

Suggested change

	let capped_last = query
	.last_block()
	.map(|end| end.min(finalized_head.number))
	.or(Some(finalized_head.number));
	capped_last
	query
	.last_block()
	.map(|end| end.min(finalized_head.number))
	.or(Some(finalized_head.number))

[Copilot]

The error message 'Finalized head is not available yet' should be more specific about the context. Consider including that this is for a finalized query, e.g., 'Cannot execute finalized query: finalized head is not available yet'.

Suggested change

	anyhow::bail!("Finalized head is not available yet");
	anyhow::bail!("Cannot execute finalized query: finalized head is not available yet");