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

tests/approvalVerify.test.js

@@ -599,6 +599,24 @@ describe("verifySignedTx field comparison", () => {
                 expect(e.message).toContain("1.0 ETH");
             }
         });
+
+        // The fee is in the native currency of the network the transaction is
+        // for, whether its chain id is the hex string the background prepares
+        // or the number ethers parses from a signed transaction.
+        test.each([
+            ["0x1", "ETH"],
+            [1n, "ETH"],
+            ["0xaa36a7", "SepoliaETH"],
+            [11155111n, "SepoliaETH"],
+        ])("the refusal on chain %p names %s", (chainId, nativeCurrency) => {
+            expect(() => assertWithinCeilings({ ...OVER, chainId })).toThrow(
+                "up to 3000.0 " +
+                    nativeCurrency +
+                    ", which is more than the 1.0 " +
+                    nativeCurrency +
+                    " this wallet",
+            );
+        });
     });
 
     test("every field mismatch is a refusal, not a warning", async () => {