Reapply "fix: use the correct l2_chain_id (succinctlabs#782)"

This reverts commit 18c6583.

I don't run into the issue described in celo-org/celo-blockchain-planning#1333 when running locally:
```
> RUST_LOG=info cargo run --bin cost-estimator --release --features eigenda -- --rolling
...
2026-02-03T10:32:36.911691Z  WARN Dropping old batch
2026-02-03T10:32:36.911699Z  INFO Found next batch (epoch #24375525)
2026-02-03T10:32:36.912176Z  INFO generated attributes in payload queue txs=18 timestamp=1770113291
2026-02-03T10:32:36.912191Z  INFO Stepped derivation pipeline
2026-02-03T10:32:36.912391Z  WARN L2PayloadWitness hint was sent, but payload witness is disabled. Skipping hint.
2026-02-03T10:32:36.912406Z  INFO Beginning block building. block_number=58212533 block_timestamp=1770113291 block_gas_limit=30000000 transactions=19
2026-02-03T10:33:48.749315Z  INFO Finished block building. Beginning sealing job. gas_used=2742971 gas_limit=30000000
2026-02-03T10:33:48.919875Z  INFO Sealed new block number=58212533 hash=0xe341f2ec74f80dcc4ea16f55beaee605be0c71feb4ef3e9acc44da9c8bca5bfb state_root=0x37725f6f987e6a8a9082722b402dabcefb05b4c2993912d30c26b61b67659286 transactions_root=0x335a0cd4692cf3a6ba1eb487dab06d81f974b5676de5bda14b22b83b7365367b receipts_root=0xee716f46288ce657e79c4ffaf6c271c9fe4fd7afe9283ff3a9fdababcb89a547
2026-02-03T10:33:48.920168Z  INFO Computing output root state_root=0x37725f6f987e6a8a9082722b402dabcefb05b4c2993912d30c26b61b67659286 block_number=58212533
2026-02-03T10:33:48.920611Z  INFO Computed output root block_number=58212533 output_root=0xc34a415f42057db7bc1d7c4ef6e7e5d7afcc51b2280a471161685d1969c553db
2026-02-03T10:33:48.920782Z  INFO Found next batch (epoch #24375525)
2026-02-03T10:33:49.258311Z  INFO generated attributes in payload queue txs=17 timestamp=1770113292
2026-02-03T10:33:49.258373Z  INFO Stepped derivation pipeline
2026-02-03T10:33:49.259932Z  WARN L2PayloadWitness hint was sent, but payload witness is disabled. Skipping hint.
2026-02-03T10:33:49.260467Z  INFO Beginning block building. block_number=58212534 block_timestamp=1770113292 block_gas_limit=30000000 transactions=18
2026-02-03T10:34:42.260792Z  INFO Finished block building. Beginning sealing job. gas_used=3548295 gas_limit=30000000
2026-02-03T10:34:42.301709Z  INFO Sealed new block number=58212534 hash=0x1c7fd5178c48b1dd24e8f99ff408a8208b77801d0f53378c897872adffbe3d72 state_root=0xa7195b1c4fb32970a35efaa7440773e241fd10b1c14e66969448bd8a50dabcff transactions_root=0x81219d080cbb83e9b351c12a007de5fe73c8f1fbb7ac87e940c778a2d28182ec receipts_root=0x46f6707abaddd4e867ed4502cbea4350a808353bb66a4436909bcf33d1754047
2026-02-03T10:34:42.301953Z  INFO Computing output root state_root=0xa7195b1c4fb32970a35efaa7440773e241fd10b1c14e66969448bd8a50dabcff block_number=58212534
2026-02-03T10:34:42.301999Z  INFO Computed output root block_number=58212534 output_root=0x404afc9ddeae7c557d1c3052a12f2388a475728d1b7964db0a58c84c70f90e10
2026-02-03T10:34:42.302087Z  INFO Found next batch (epoch #24375525)
2026-02-03T10:34:42.634595Z  INFO generated attributes in payload queue txs=23 timestamp=1770113293
2026-02-03T10:34:42.634659Z  INFO Stepped derivation pipeline
2026-02-03T10:34:42.636056Z  WARN L2PayloadWitness hint was sent, but payload witness is disabled. Skipping hint.
2026-02-03T10:34:42.636116Z  INFO Beginning block building. block_number=58212535 block_timestamp=1770113293 block_gas_limit=30000000 transactions=24
2026-02-03T10:35:26.885955Z  INFO Finished block building. Beginning sealing job. gas_used=3066866 gas_limit=30000000
2026-02-03T10:35:26.891901Z  INFO Sealed new block number=58212535 hash=0x4a2f90e82b0dae002adae3c2d5dbae79e611726fe0a54ea1dcdbbb2aa9e42ddd state_root=0xec76d2337c99b8c616844cab193df83b560f720fa7384a7b41659fcdbdb48060 transactions_root=0xb354bbe17384131642f5266a089ed1717c54384fc38f878501ffd19508f5f4d6 receipts_root=0x567272c03852a45e2a291c9dd5824064924c0c83397510ec87000b9f1b884c09
2026-02-03T10:35:26.892081Z  INFO Computing output root state_root=0xec76d2337c99b8c616844cab193df83b560f720fa7384a7b41659fcdbdb48060 block_number=58212535
2026-02-03T10:35:26.892121Z  INFO Computed output root block_number=58212535 output_root=0x6a99c7d0716856d7901e76899d38ca5f496ea4abb96c7745d858a6c01b1522e2
2026-02-03T10:35:26.892191Z  INFO Found next batch (epoch #24375525)
2026-02-03T10:35:27.230887Z  INFO generated attributes in payload queue txs=21 timestamp=1770113294
2026-02-03T10:35:27.230963Z  INFO Stepped derivation pipeline
2026-02-03T10:35:27.232898Z  WARN L2PayloadWitness hint was sent, but payload witness is disabled. Skipping hint.
2026-02-03T10:35:27.233310Z  INFO Beginning block building. block_number=58212536 block_timestamp=1770113294 block_gas_limit=30000000 transactions=22
2026-02-03T10:36:24.240624Z  INFO Finished block building. Beginning sealing job. gas_used=3362763 gas_limit=30000000
2026-02-03T10:36:24.250645Z  INFO Sealed new block number=58212536 hash=0x7fd84573b0f48c33d1c12ae7bf35a42a0ca6331363a7efa77293af3f550838e2 state_root=0xf5f8d11a1eb46051a44ee759e3ead2a07a4ed580194ae89759ece58d13b922f6 transactions_root=0x1b1990bd5f4ea04448c6a5ca67ad5086437e66d99041f5b42875ad449f14fb18 receipts_root=0xbc7990712ef8c161bcca2d61aeb1903d8870f631116e93f250d6ab0278786877
2026-02-03T10:36:24.251157Z  INFO Computing output root state_root=0xf5f8d11a1eb46051a44ee759e3ead2a07a4ed580194ae89759ece58d13b922f6 block_number=58212536
2026-02-03T10:36:24.251592Z  INFO Computed output root block_number=58212536 output_root=0x5ea470ad3ddbe05157bb4f366a3ca79a82ea247b50884c658f2415d403646a01
2026-02-03T10:36:24.251747Z  INFO Found next batch (epoch #24375525)
2026-02-03T10:36:24.585804Z  INFO generated attributes in payload queue txs=16 timestamp=1770113295
2026-02-03T10:36:24.585826Z  INFO Stepped derivation pipeline
2026-02-03T10:36:24.586290Z  WARN L2PayloadWitness hint was sent, but payload witness is disabled. Skipping hint.
2026-02-03T10:36:24.586319Z  INFO Beginning block building. block_number=58212537 block_timestamp=1770113295 block_gas_limit=30000000 transactions=17
2026-02-03T10:37:08.046695Z  INFO Finished block building. Beginning sealing job. gas_used=3458116 gas_limit=30000000
2026-02-03T10:37:08.054902Z  INFO Sealed new block number=58212537 hash=0xebf2e24ea3aa85c09656e0861813333fe9e2198c07ea84b3bb67b1ce531632c3 state_root=0xd02b131fdedb063b4e02097327f3eec0a8330597e81e0c8e5a28896f6b15e62a transactions_root=0x1167ef97a9211173c20a81482b60cd70d54379e15bf6b50f2a3e4f3607686626 receipts_root=0x75b78587956a4527a0f5a05d48a15da8c3be75ca7a8138fb1819d84fb9c150ee
2026-02-03T10:37:08.055214Z  INFO Computing output root state_root=0xd02b131fdedb063b4e02097327f3eec0a8330597e81e0c8e5a28896f6b15e62a block_number=58212537
2026-02-03T10:37:08.055438Z  INFO Computed output root block_number=58212537 output_root=0x8076d593316eeec6a15d59cab5b712f081858e9dc58d13709ad65c0bf94bbf04
2026-02-03T10:37:08.055537Z  INFO Derivation complete, reached L2 safe head.
2026-02-03T10:37:08.055544Z  INFO Successfully validated L2 block #58212537 with output root 0x8076d593316eeec6a15d59cab5b712f081858e9dc58d13709ad65c0bf94bbf04
2026-02-03T10:37:50.764147Z  INFO completed 3 kzg proofs generation in 42.706973417s times
2026-02-03T10:37:50.764780Z  INFO producing 1 canoe proof for 3 DA certs
2026-02-03T10:37:50.764826Z  INFO begin to generate a sp1-cc proof for 3 number of altda commitment at l1 block number 24375657 with chainID 1
2026-02-03T10:38:12.023363Z  INFO fetching storage proofs
2026-02-03T10:38:16.122128Z  INFO fetching 0 ancestor headers
2026-02-03T10:38:16.124280Z  WARN SP1_CC_PROOF_STRATEGY not set; using Reserved as the default strategy
2026-02-03T10:38:16.124292Z  WARN NETWORK_PRIVATE_KEY is not set, using default network private key
2026-02-03T10:38:23.002773Z  INFO Requesting proof:
2026-02-03T10:38:23.002827Z  INFO ├─ Strategy: Reserved
2026-02-03T10:38:23.002836Z  INFO ├─ Proof mode: Compressed
2026-02-03T10:38:23.002849Z  INFO ├─ Circuit version: v5.0.0
2026-02-03T10:38:23.002856Z  INFO ├─ Timeout: 14400 seconds
2026-02-03T10:38:23.002863Z  INFO ├─ Cycle limit: 1000000000000 cycles
2026-02-03T10:38:23.002870Z  INFO └─ Gas limit: 1000000000000 PGUs
2026-02-03T10:38:28.016741Z ERROR Permanent error encountered when requesting proof: no reservation found for requester (The caller does not have permission to execute the specified operation)
```

Author: karlb

utils/host/src/fetcher.rs

@@ -697,10 +697,9 @@ impl OPSuccinctDataFetcher {
         l2_end_block: u64,
         l1_head_hash: B256,
     ) -> Result<SingleChainHost> {
-        // If the rollup config is not already loaded, fetch and save it.
-        if self.rollup_config.is_none() {
+        let Some(rollup_config) = &self.rollup_config else {
             return Err(anyhow::anyhow!("Rollup config not loaded."));
-        }
+        };
 
         if l2_start_block >= l2_end_block {
             return Err(anyhow::anyhow!(
@@ -763,7 +762,7 @@ impl OPSuccinctDataFetcher {
             agreed_l2_head_hash,
             claimed_l2_output_root,
             claimed_l2_block_number: l2_end_block,
-            l2_chain_id: None,
+            l2_chain_id: Some(rollup_config.l2_chain_id.id()),
             // Trim the trailing slash to avoid double slashes in the URL.
             l2_node_address: Some(
                 self.rpc_config.l2_rpc.as_str().trim_end_matches('/').to_string(),