deployment: add sepolia-alpha native config override layer

Translate the sepolia-alpha config.sequencerConfig overrides (the public
common.yaml + services/*.yaml flat dotted keys) into the nested
sequencer_config.jsonnet override layer the native config builder consumes,
mirroring the existing sepolia-integration layer. Add a regression test
asserting the jsonnet layer stays in lockstep with the combined YAML overrides
(folded: #is_none applied, components dropped).

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

Author: nimrod-starkware

deployments/sequencer/configs/overlays/hybrid/sepolia-alpha/sequencer_config.jsonnet

@@ -0,0 +1,82 @@
+// Overrides layer for the `sepolia-alpha` environment (hybrid layout).
+{
+  chain_id: 'SN_SEPOLIA',
+  native_classes_whitelist: 'All',
+  recorder_url: 'http://starknet-sepolia-alpha.cende-recorder-proxy.starknet.io/',
+  starknet_url: 'https://feeder.alpha-sepolia.starknet.io/',
+
+  base_layer_config: {
+    bpo1_start_block_number: 9456501,
+    bpo2_start_block_number: 9504747,
+    fusaka_no_bpo_start_block_number: 9408577,
+    starknet_contract_address: '0xE2Bb56ee936fd6433DC0F6e7e3b8365C906AA057',
+  },
+
+  batcher_config: {
+    dynamic_config: {
+      n_concurrent_txs: 8,
+    },
+    static_config: {
+      block_builder_config: {
+        bouncer_config: {
+          block_max_capacity: {
+            state_diff_size: 5000,
+          },
+        },
+        execute_config: {
+          n_workers: 5,
+        },
+      },
+      first_block_with_partial_block_hash: {
+        block_hash: '0x578b4e2f34e4da24e7482de643b4e3435fa7e34770cdb8d71002bb19e415ffa',
+        block_number: 86311,
+        parent_block_hash: '0x5c980ea7747167d2ae98fa7ef7d62f52243e924c453b4934045443d977458d3',
+      },
+    },
+  },
+
+  committer_config: {
+    storage_config: {
+      cache_size: 10000000,
+      inner_storage_config: {
+        cache_size: 1073741824,
+      },
+    },
+  },
+
+  consensus_manager_config: {
+    context_config: {
+      dynamic_config: {
+        min_l2_gas_price_per_height: '',
+      },
+    },
+    staking_manager_config: {
+      dynamic_config: {
+        default_committee: '0,10:0x64,1,0x1,true;0x65,1,0x1,true;0x66,1,0x1,true;0x67,1,0x1,true;0x68,1,0x1,true',
+      },
+    },
+  },
+
+  gateway_config: {
+    static_config: {
+      proof_archive_writer_config: {
+        bucket_name: 'starkware-starknet-alpha',
+      },
+    },
+  },
+
+  sierra_compiler_config: {
+    audited_libfuncs_only: true,
+  },
+
+  state_sync_config: {
+    static_config: {
+      central_sync_client_config: {
+        sync_config: {
+          store_sierras_and_casms_block_threshold: 0,
+        },
+      },
+      network_config: null,
+    },
+  },
+}

deployments/sequencer/test/test_native_config.py

@@ -46,6 +46,7 @@
 HYBRID_OVERLAYS_DIR = DEPLOYMENTS_SEQUENCER / "configs" / "overlays" / LAYOUT
 COMMON_LAYER_DIR = HYBRID_OVERLAYS_DIR / "common"
 INTEGRATION_LAYER_DIR = HYBRID_OVERLAYS_DIR / "sepolia-integration"
+SEPOLIA_ALPHA_LAYER_DIR = HYBRID_OVERLAYS_DIR / "sepolia-alpha"
 
 # The committed dump of Rust `private_parameters()` (the secrets): every non-pointer private param
 # plus every pointer target pointed by a private param. These are filled at deploy from the
@@ -600,6 +601,11 @@ def test_integration_layer_jsonnet_mirrors_combined_yaml():
     _assert_layer_jsonnet_mirrors_combined_yaml(INTEGRATION_LAYER_DIR)
 
 
+def test_sepolia_alpha_layer_jsonnet_mirrors_combined_yaml():
+    """REGRESSION: same invariant for the `sepolia-alpha` env layer."""
+    _assert_layer_jsonnet_mirrors_combined_yaml(SEPOLIA_ALPHA_LAYER_DIR)
+
+
 def _relative_layer_files(overlays_root: Path) -> set[str]:
     """Every overlay file under `overlays_root`, as posix paths relative to that root."""
     return {