feat: show estimated USD value for ETH in approve-tx view

Use getPrice/formatUsd from shared/prices to display the USD estimate
next to the ETH amount in the dapp transaction approval view, matching
the behavior already present in the manual send confirmation view.

closes #138

src/popup/views/approval.js

@@ -9,6 +9,7 @@ const {
 } = require("./helpers");
 const { state, saveState } = require("../../shared/state");
 const { formatEther, formatUnits, Interface, toUtf8String } = require("ethers");
+const { getPrice, formatUsd } = require("../../shared/prices");
 const { ERC20_ABI } = require("../../shared/constants");
 const { TOKEN_BY_ADDRESS } = require("../../shared/tokenList");
 const txStatus = require("./txStatus");
@@ -243,8 +244,14 @@ function showTxApproval(details) {
         $("approve-tx-to").innerHTML = escapeHtml("(contract creation)");
     }
 
+    const ethValueFormatted = formatTxValue(
+        formatEther(details.txParams.value || "0"),
+    );
+    const ethPrice = getPrice("ETH");
+    const ethUsd = ethPrice ? parseFloat(ethValueFormatted) * ethPrice : null;
+    const usdStr = formatUsd(ethUsd);
     $("approve-tx-value").textContent =
-        formatTxValue(formatEther(details.txParams.value || "0")) + " ETH";
+        ethValueFormatted + " ETH" + (usdStr ? " (" + usdStr + ")" : "");
 
     // Decode calldata (reuse decoded from above)
     const decodedEl = $("approve-tx-decoded");