fix: a V4 swap action not in the deployed shape is shown as not decoded (closes #358)

The four V4 swap actions are read only as the structs deployed on mainnet
and Sepolia. ethers read the newer v4-periphery structs, which add
minHopPriceX36, as the deployed ones, and the newer multi-hop exact-in
struct showed the offset of its hop-price array as the swap amount. A
decode now counts only when encoding it again gives back the same bytes.
A swap action that fails that marks its step "V4 Swap (could not be
decoded)", and a side its SETTLE or TAKE did not name reads "Unknown
(could not be decoded)". The wait and error screens no longer show the
ETH value as the amount of a swap whose amount was not read, unless the
swap is paid in native ETH.

Model: opus-5-5

src/popup/views/approval.js

@@ -298,6 +298,23 @@ function showTxApproval(details) {
                 sources,
             );
         }
+        // A swap the decoder read no amount for, such as one whose V4 swap
+        // action could not be read or a V4 exact-out swap. The wait and error
+        // screens say the amount could not be decoded, with no currency after
+        // it, rather than show the transaction's ETH value as the amount. A
+        // swap paid in native ETH keeps that value: it is the ETH the swap
+        // pays (for an exact-out swap, the most it pays), not a figure that
+        // had to be read from the calldata.
+        const tokenIn = decoded.details.find((d) => d.label === "Token In");
+        if (
+            tokenIn &&
+            tokenIn.value !== "ETH (native)" &&
+            !decoded.details.some((d) => d.label === "Amount")
+        ) {
+            pendingTxDetails.amount = "Unknown (could not be decoded)";
+            pendingTxDetails.token = null;
+            pendingTxDetails.tokenSymbol = null;
+        }
     }
 
     // Carry decoded calldata info through to success/error views