docs(l2): add guide to re generate blobs

docs/SUMMARY.md

@@ -76,6 +76,7 @@
 - [L2](./developers/l2/introduction.md)
   - [Ethrex L2 as local development mode](./developers/l2/dev-mode.md)
   - [Integration tests](./developers/l2/integration-tests.md)
+  - [Generate blobs for the state reconstruction test](./developers/l2/state-reconstruction-blobs.md)
 - [Debugging solidity with ethrex](./vm/levm/debug.md)
 - [Re-execute Ethereum with ethrex](./ethrex_replay/ethrex_replay.md)
   - [FAQ](./ethrex_replay/faq.md)

docs/developers/l2/state-reconstruction-blobs.md

@@ -0,0 +1,50 @@
+# Generate blobs for the state reconstruction test
+
+The test in `crates/l2/tests/state_reconstruct.rs` replays a fixed set of blobs to reconstruct. If you ever need to regenerate those fixtures, you need to change the files `payload_builder.rs` and `l1_committer.rs`.
+
+## 1. Cap block payloads at 10 transactions
+
+Edit `crates/l2/sequencer/block_producer/payload_builder.rs` and, inside the `fill_transactions` loop, add the early exit that forces every L2 block to contain at most ten transactions:
+
+```rust
+if context.payload.body.transactions.len() >= 10 {
+    println!("Reached max transactions per block limit");
+    break;
+}
+```
+
+That guarantees we have transactions in each block for at least 6 batches.
+
+## 2. Persist every blob locally when the committer sends a batch
+
+Still in the sequencer, open `crates/l2/sequencer/l1_committer.rs`:
+
+- At the end of `send_commitment` (after logging the transaction hash) dump the blob that was just submitted:
+
+  ```rust
+  // Rest of the code ...
+  info!("Commitment sent: {commit_tx_hash:#x}");
+  store_blobs(batch.blobs_bundle.blobs.clone(), batch.number);
+  Ok(commit_tx_hash)
+  ```
+
+- Add this helper function:
+
+  ```rust
+  fn store_blobs(blobs: Vec<Blob>, current_blob: u64) {
+      let blob = blobs.first().unwrap();
+      fs::write(format!("{current_blob}-1.blob"), blob).unwrap();
+  }
+  ```
+
+Running the node with the deposits of the rich accounts will create `N-1.blob` files (you can move them into `fixtures/blobs/` afterwards).
+
+## 3. Run the L2 and capture six blobs
+
+Start the local L2 with a 20 seconds per commit so we have at least 6 batches with transactions:
+
+```sh
+ethrex l2 --dev --no-monitor --committer.commit-time 20000
+```
+
+Once the sequencer has produced six batches you will see six files named `1-1.blob` through `6-1.blob`. Copy them into `fixtures/blobs/` (overwriting the existing files).