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/popup/views/approval.js

@@ -12,7 +12,10 @@ const {
     formatFee,
 } = require("./helpers");
 const { state, saveState } = require("../../shared/state");
-const { networkByChainId } = require("../../shared/networks");
+const {
+    networkByChainId,
+    nativeCurrencyByChainId,
+} = require("../../shared/networks");
 const {
     formatEther,
     formatUnits,
@@ -219,8 +222,12 @@ function showTxFee(approvedTx) {
     const gasLimit = BigInt(approvedTx.gasLimit);
     const feePerGas = BigInt(approvedTx.maxFeePerGas || approvedTx.gasPrice);
     // Through formatFee(), as the confirmation screen's fee is, so the same
-    // fee reads the same on both.
-    $("approve-tx-fee").textContent = formatFee(gasLimit * feePerGas);
+    // fee reads the same on both. In the native currency of the network shown
+    // above, as the value is.
+    $("approve-tx-fee").textContent = formatFee(
+        gasLimit * feePerGas,
+        nativeCurrencyByChainId(approvedTx.chainId),
+    );
 
     let detail =
         gasLimit.toString() +
@@ -264,6 +271,7 @@ function showTxApproval(details) {
         amount: formatTxValue(ethValue),
         token: "ETH",
         tokenSymbol: null,
+        chainId: approvedTx.chainId,
     };
 
     // If this is an ERC-20 call, try to extract the real recipient and amount
@@ -329,8 +337,15 @@ function showTxApproval(details) {
     const ethPrice = getPrice("ETH");
     const ethUsd = ethPrice ? parseFloat(ethValueFormatted) * ethPrice : null;
     const usdStr = formatUsd(ethUsd);
+    // In the native currency of the network the transaction is for, which the
+    // Network line names, not the active network's: a site can switch the
+    // active network after this transaction is prepared and back before it is
+    // signed.
     $("approve-tx-value").textContent =
-        ethValueFormatted + " ETH" + (usdStr ? " (" + usdStr + ")" : "");
+        ethValueFormatted +
+        " " +
+        nativeCurrencyByChainId(approvedTx.chainId) +
+        (usdStr ? " (" + usdStr + ")" : "");
 
     showTxFee(approvedTx);