chore: the native token's label follows the network (closes #372)

networks.js gives each network a nativeCurrency (ETH, SepoliaETH) and nothing
read it: every screen wrote ETH. The wallet's balances and the Send and
confirmation screens now use the active network's. A transaction's figures use
the network its chain id names, through nativeCurrencyByChainId(): the
approval value and fee, the wait, success and error screens, history entries,
the detail screen and the fee-limit refusal, so a site switching networks
cannot make one read as another network's coin. The "ETH" that selectedToken
and txInfo.token hold is the native token's id and is unchanged. A token
reporting any network's nativeCurrency is a spoof, and the detail screen calls
an entry a token transfer when it has a token contract.

Model: opus-5-5

src/shared/approvalVerify.js

@@ -54,9 +54,11 @@ const {
     formatEther,
     getAddress,
     getBytes,
+    toQuantity,
     verifyMessage,
     verifyTypedData,
 } = require("ethers");
+const { nativeCurrencyByChainId } = require("./networks");
 
 // The only transaction types this wallet signs: legacy, EIP-2930 and
 // EIP-1559. populateTransaction() produces nothing else, so nothing else can
@@ -407,12 +409,21 @@ function assertWithinCeilings(tx) {
             price = normalizeQuantity(tx.gasPrice, "gas price");
         }
         if (price !== null && gasLimit * price > MAX_TOTAL_FEE) {
+            // The fee is paid in the native currency of the network the
+            // transaction is for. Every caller's transaction names it.
+            const nativeCurrency = nativeCurrencyByChainId(
+                present(tx.chainId) ? toQuantity(tx.chainId) : null,
+            );
             throw refuse(
                 "This transaction would allow a network fee of up to " +
                     formatEther(gasLimit * price) +
-                    " ETH, which is more than the " +
+                    " " +
+                    nativeCurrency +
+                    ", which is more than the " +
                     formatEther(MAX_TOTAL_FEE) +
-                    " ETH this wallet will sign for.",
+                    " " +
+                    nativeCurrency +
+                    " this wallet will sign for.",
             );
         }
     }