feat(l2): generate batch prover input at commit and store it in db

[ilitteri]

Motivation

We want to persist batch prover inputs to avoid having to regenerate them in case of an unexpected shutdown. We also want to store the version of the binary that generated them to be able to prove yet-unproven batches from older ethrex versions.

Description

This PR:

• Extends the L2 store functionality to support storing and retrieving batch prover inputs.
• For the SQL store, a new table batch_prover_input is created with rows prover_input (actual rkyv-encoded ProverInputData), batch_number, and prover_version, being the tuple of the last two the primary key.
• For the in-memory store, a new hash map batch_prover_input is created with key (batch_number, prover_version) and value witness (actual rkyv-encoded ProverInputData).
• The committer now generates and stores the batch prover inputs in the L2 store.
• The proof coordinator now retrieves the batch prover inputs from the L2 store.
• ProverInputData is moved to the ethrex-l2-common crate, as it is now a common data structure between different crates.
• The prover client now requests batch prover input data specifying both batch number and binary version.

Future work

With this new feature, an older prover should be able to retrieve data from an upgraded sequencer, as long as there are batches to be proven in that version. Currently it rejects any request from a different version.

[github-actions]

Lines of code report

Total lines added: 251
Total lines removed: 111
Total lines changed: 362

Detailed view

+----------------------------------------------------+-------+------+
| File                                               | Lines | Diff |
+----------------------------------------------------+-------+------+
| ethrex/crates/l2/common/src/prover.rs              | 127   | +17  |
+----------------------------------------------------+-------+------+
| ethrex/crates/l2/sequencer/errors.rs               | 356   | +4   |
+----------------------------------------------------+-------+------+
| ethrex/crates/l2/sequencer/l1_committer.rs         | 781   | +59  |
+----------------------------------------------------+-------+------+
| ethrex/crates/l2/sequencer/mod.rs                  | 222   | -2   |
+----------------------------------------------------+-------+------+
| ethrex/crates/l2/sequencer/proof_coordinator.rs    | 482   | -109 |
+----------------------------------------------------+-------+------+
| ethrex/crates/l2/sequencer/utils.rs                | 178   | +38  |
+----------------------------------------------------+-------+------+
| ethrex/crates/l2/storage/src/api.rs                | 120   | +11  |
+----------------------------------------------------+-------+------+
| ethrex/crates/l2/storage/src/store.rs              | 311   | +19  |
+----------------------------------------------------+-------+------+
| ethrex/crates/l2/storage/src/store_db/in_memory.rs | 327   | +39  |
+----------------------------------------------------+-------+------+
| ethrex/crates/l2/storage/src/store_db/sql.rs       | 853   | +64  |
+----------------------------------------------------+-------+------+

[Copilot]

Pull Request Overview

This PR adds functionality to persist batch prover inputs to the L2 store, enabling recovery after unexpected shutdowns and supporting proofs for batches from older ethrex versions.

Key Changes:

• Added database schema and storage layer methods to store/retrieve batch prover inputs keyed by batch number and prover version
• Moved ProverInputData to ethrex-l2-common crate for cross-crate usage
• Modified the committer to generate and persist batch prover inputs during commit operations
• Updated the proof coordinator to retrieve prover inputs from storage instead of regenerating them

Reviewed Changes

Copilot reviewed 15 out of 16 changed files in this pull request and generated 3 comments.

Show a summary per file

File	Description
crates/l2/storage/src/store_db/sql.rs	Adds SQL table schema and implementation for storing/retrieving batch prover inputs
crates/l2/storage/src/store_db/in_memory.rs	Adds in-memory storage implementation for batch prover inputs
crates/l2/storage/src/store.rs	Adds public API methods for storing/retrieving batch prover inputs
crates/l2/storage/src/api.rs	Defines trait methods for batch prover input operations
crates/l2/storage/Cargo.toml	Adds rkyv dependency for serialization
crates/l2/sequencer/utils.rs	Adds utility function to fetch blocks for a given batch
crates/l2/sequencer/proof_coordinator.rs	Removes prover input generation logic and retrieves inputs from storage instead
crates/l2/sequencer/mod.rs	Removes unused dependencies from ProofCoordinator::spawn
crates/l2/sequencer/l1_committer.rs	Adds batch prover input generation and storage during commit operations
crates/l2/sequencer/errors.rs	Adds new error variants for missing prover inputs and witness generation failures
crates/l2/prover/src/prover.rs	Updates batch request to include binary version
crates/l2/l2.rs	Adds constants module
crates/l2/constants.rs	Defines binary version constant from package version
crates/l2/common/src/prover.rs	Moves ProverInputData definition here and adds rkyv serialization support
crates/l2/common/Cargo.toml	Adds rkyv and serde_with dependencies

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[Copilot]

The error message says 'witness' but should say 'prover input' to match the actual data being serialized (ProverInputData).