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
Co-authored-by: clawbot <clawbot@noreply.example.org>

src/shared/uniswap.js

@@ -2,10 +2,10 @@
 // swap details.  Designed to be extended with other DEX decoders later.
 
 const { Interface, AbiCoder, getBytes, formatUnits } = require("ethers");
-const { TOKEN_BY_ADDRESS } = require("./tokenList");
 const { truncateAmountNeverZero } = require("./amountDisplay");
 const {
     resolveTokenDecimals,
+    resolveTokenSymbol,
     unknownDecimalsAmount,
 } = require("./approvalAmount");
 
@@ -123,9 +123,8 @@ function tokenInfo(address, sources) {
     if (address === "0x0000000000000000000000000000000000000000") {
         return { symbol: "ETH", decimals: 18, address: null };
     }
-    const t = TOKEN_BY_ADDRESS.get(address.toLowerCase());
     return {
-        symbol: t ? t.symbol : null,
+        symbol: resolveTokenSymbol(address, sources),
         decimals: resolveTokenDecimals(address, sources),
         address,
     };