feat(bridge-withdrawer): bridge withdrawer startup

crates/astria-bridge-withdrawer/local.env.example

@@ -34,6 +34,9 @@ ASTRIA_BRIDGE_WITHDRAWER_SEQUENCER_KEY_PATH=/path/to/priv_sequencer_key.json
 # The fee asset denomination to use for the bridge account's transactions.
 ASTRIA_BRIDGE_WITHDRAWER_FEE_ASSET_DENOMINATION="nria"
 
+# The minimum expected balance of the fee asset in the bridge account.
+ASTRIA_BRIDGE_WITHDRAWER_MIN_EXPECTED_FEE_ASSET_BALANCE=1000000
+
 # The asset denomination being withdrawn from the rollup.
 ASTRIA_BRIDGE_WITHDRAWER_ROLLUP_ASSET_DENOMINATION="nria",
 

crates/astria-bridge-withdrawer/src/config.rs

@@ -17,6 +17,8 @@ pub struct Config {
     pub sequencer_key_path: String,
     // The fee asset denomination to use for the bridge account's transactions.
     pub fee_asset_denomination: String,
+    // The minimum expected balance of the fee asset in the bridge account.
+    pub min_expected_fee_asset_balance: u64,
     // The asset denomination being withdrawn from the rollup.
     pub rollup_asset_denomination: String,
     // The address of the AstriaWithdrawer contract on the evm rollup.

crates/astria-bridge-withdrawer/src/withdrawer/ethereum/convert.rs

@@ -113,6 +113,7 @@ fn event_to_bridge_unlock(
         memo: serde_json::to_vec(&memo).wrap_err("failed to serialize memo to json")?,
         fee_asset_id,
     };
+
     Ok(Action::BridgeUnlock(action))
 }