fix: name a tracked or explorer-known token instead of "Unknown token" (closes #323)

The approval and transaction-status screens read a token's scale from the
bundled list, the tokens the user tracks, then the block explorer, but read
its symbol from the bundled list alone. A token the user added by hand was
scaled correctly yet labelled "Unknown token", and a non-bundled ERC-20 was
carried onto the wait screen as ETH.

resolveTokenSymbol() now draws the symbol through the same sources and
precedence as the scale, and the ERC-20 and Uniswap swap lines both use it. A
tracked or explorer-reported name stays subject to the spoof rule, so it
cannot claim a bundled or native ticker.

Folds in #354.

Model: opus-4-8

tests/fabricatedDecimals.test.js

@@ -253,8 +253,9 @@ describe("the ERC-20 approval line reaches its refusal", () => {
 
     test("a scale the explorer did report still formats", async () => {
         await fetchOnto([row({ decimals: "6" })]);
+        // The same explorer entry now also names the token (issue #323).
         expect(erc20AmountLine(transferData(THOUSAND_AT_SIX), NOVEL)).toBe(
-            "1000.0000",
+            "1000.0000 NOVEL",
         );
     });
 });
@@ -273,7 +274,7 @@ describe("the swap approval line reaches its refusal", () => {
         await fetchOnto([row({ decimals: "6" })]);
         expect(
             swapAmountLine(swapData(NOVEL, THOUSAND_AT_SIX, WETH, HALF_WETH)),
-        ).toBe("1000.0000");
+        ).toBe("1000.0000 NOVEL");
     });
 });