fix: say an unknown-scale balance the same way on Send and on confirm (closes #377)

When two addresses' explorer reports disagree on a token's decimals, the
Send screen showed the stored figure while the confirmation screen said
the balance was unknown. One function in send.js now gives both the
balance and scale, so both read `unknown (SYMBOL)`.

The confirmation screen's fee-unknown message names its cause: for an
unknown scale it says the wallet does not know the token's decimal
places and the transaction cannot be sent, instead of asking for a
retry that cannot help. Other causes keep the old sentence.

Model: opus-5-5

tests/unknownScaleSend.test.js

@@ -382,8 +382,56 @@ describe("a scale the explorer's own rows disagree about", () => {
         );
     });
 
+    // https://git.eeqj.de/sneak/AutistMask/issues/377. The Send screen read the
+    // stored balance and said "5.0000 NOVEL", the confirmation screen it leads
+    // to said "unknown (NOVEL)", and the fee message asked the user to go back
+    // and try again, which cannot supply a scale.
+    test("reads the same on the Send screen and the confirmation screen, and the fee message names the scale", async () => {
+        await fetchOntoBoth([novel("6", 5000000n)], [novel("18", FIVE_WETH)]);
+        state.selectedToken = NOVEL;
+        send.updateSendBalance();
+        expect(text("send-balance")).toBe("Current balance: unknown (NOVEL)");
+
+        const txInfo = await reviewSend(NOVEL, "1.5");
+        confirmTx.show(txInfo);
+        await settle();
+        expect(text("confirm-balance")).toBe("unknown (NOVEL)");
+        expect(text("confirm-fee-unknown-error")).toBe(
+            "The network fee could not be estimated, because this wallet" +
+                " does not know how many decimal places this token uses, so" +
+                " this transaction cannot be sent.",
+        );
+        expect(el("confirm-fee-unknown-error").style.visibility).toBe(
+            "visible",
+        );
+    });
+
+    test("while a fee that fails for any other reason keeps its retry", async () => {
+        await fetchOntoBoth([novel("6", 5000000n)], [novel("6", 5000000n)]);
+        const txInfo = await reviewSend(NOVEL, "1.5");
+        const getFeeData = mockProvider.getFeeData;
+        mockProvider.getFeeData = async () => {
+            throw new Error("the node did not answer");
+        };
+        try {
+            confirmTx.show(txInfo);
+            await settle();
+        } finally {
+            mockProvider.getFeeData = getFeeData;
+        }
+        expect(text("confirm-fee-amount")).toBe("Unable to estimate");
+        expect(text("confirm-fee-unknown-error")).toBe(
+            "The network fee could not be estimated, so this transaction" +
+                " cannot be checked against your balance. Please go back and" +
+                " try again.",
+        );
+    });
+
     test("while agreeing rows leave the scale usable", async () => {
         await fetchOntoBoth([novel("6", 5000000n)], [novel("6", 5000000n)]);
+        state.selectedToken = NOVEL;
+        send.updateSendBalance();
+        expect(text("send-balance")).toBe("Current balance: 5.0000 NOVEL");
         const txInfo = await reviewSend(NOVEL, "1.5");
         expect(txInfo.tokenDecimals).toBe(6);
         expect(txInfo.tokenBalance).toBe("5.0");