improve(RelayerConfig): Permit symbol-based token config (#1460)

This change permits the InventoryConfig to be specified in either
HubPool token address or token symbol. Token symbol is preferred because
it's simpler to configure and reduces the chance of mistakes.

During parsing, any symbols are resolved to their underlying token
addresses on the HubPool chain, so no subsequent changes are required
for any accesses into the post-processed inventory config.

src/relayer/RelayerConfig.ts

@@ -1,3 +1,4 @@
+import { utils as ethersUtils } from "ethers";
 import { typeguards } from "@across-protocol/sdk-v2";
 import {
   BigNumber,
@@ -145,11 +146,23 @@ export class RelayerConfig extends CommonConfig {
         }
       });
 
-      Object.keys(inventoryConfig?.tokenConfig ?? {}).forEach((l1Token) => {
-        Object.keys(inventoryConfig.tokenConfig[l1Token]).forEach((chainId) => {
-          const tokenConfig = inventoryConfig.tokenConfig[l1Token][chainId];
+      const rawTokenConfigs = inventoryConfig?.tokenConfig ?? {};
+      const tokenConfigs = (inventoryConfig.tokenConfig = {});
+      Object.keys(rawTokenConfigs).forEach((l1Token) => {
+        // If the l1Token is a symbol, resolve the correct address.
+        const effectiveL1Token = ethersUtils.isAddress(l1Token)
+          ? l1Token
+          : TOKEN_SYMBOLS_MAP[l1Token]?.addresses[this.hubPoolChainId];
+        assert(effectiveL1Token !== undefined, `No token identified for ${l1Token}`);
+
+        Object.keys(rawTokenConfigs[l1Token]).forEach((chainId) => {
+          const { targetPct, thresholdPct, unwrapWethThreshold, unwrapWethTarget, targetOverageBuffer } =
+            rawTokenConfigs[l1Token][chainId];
+
+          tokenConfigs[effectiveL1Token] ??= {};
+          tokenConfigs[effectiveL1Token][chainId] ??= { targetPct, thresholdPct, targetOverageBuffer };
+          const tokenConfig = tokenConfigs[effectiveL1Token][chainId];
 
-          const { targetPct, thresholdPct, unwrapWethThreshold, unwrapWethTarget, targetOverageBuffer } = tokenConfig;
           assert(
             targetPct !== undefined && thresholdPct !== undefined,
             `Bad config. Must specify targetPct, thresholdPct for ${l1Token} on ${chainId}`
@@ -167,7 +180,7 @@ export class RelayerConfig extends CommonConfig {
           tokenConfig.targetOverageBuffer = toBNWei(targetOverageBuffer ?? "1.5");
 
           // For WETH, also consider any unwrap target/threshold.
-          if (l1Token === TOKEN_SYMBOLS_MAP.WETH.addresses[this.hubPoolChainId]) {
+          if (effectiveL1Token === TOKEN_SYMBOLS_MAP.WETH.addresses[this.hubPoolChainId]) {
             if (unwrapWethThreshold !== undefined) {
               tokenConfig.unwrapWethThreshold = toBNWei(unwrapWethThreshold);
             }