fix: the bundled token list names tokens on Ethereum Mainnet only (closes #632)

bundledToken(address, chainId) in tokenList.js answers only for Ethereum
Mainnet's chain id. Every reader of the bundled list now goes through it,
with the chain id of the transaction, balance or history entry it draws.
The token sources the screens build carry that chain id. The Uniswap
decoder sets the transaction's chain id on them. fetchTokenBalances()
takes the chain id of the network it asks about.

Seven existing tests read the bundled list without naming a network. Each
now names Ethereum Mainnet.

Model: opus-5-5

src/shared/approvalAmount.js

@@ -29,7 +29,7 @@
 // string, and a token the user added by hand carries whatever lookupTokenInfo()
 // got back, so the accepted types are enumerated rather than coerced.
 const { toDecimals } = require("./transferAmount");
-const { TOKEN_BY_ADDRESS } = require("./tokenList");
+const { bundledToken } = require("./tokenList");
 const { isSpoofedSymbol } = require("./symbolSpoof");
 
 // Every decimals the explorer reported for this contract, across all the
@@ -53,12 +53,14 @@ function explorerDecimals(lower, wallets) {
 }
 
 // The decimals to render a token amount with, or null when nothing knows.
-// `sources` is { trackedTokens, wallets }, both shaped as they are on `state`.
+// `sources` is { chainId, trackedTokens, wallets }. `chainId` is the chain id
+// of the token's network. The bundled list is read only when that network is
+// Ethereum Mainnet. `trackedTokens` and `wallets` are shaped as on `state`.
 function resolveTokenDecimals(tokenAddress, sources) {
     const lower = (tokenAddress || "").toLowerCase();
     if (!lower) return null;
 
-    const bundled = TOKEN_BY_ADDRESS.get(lower);
+    const bundled = bundledToken(lower, sources && sources.chainId);
     if (bundled) {
         const d = toDecimals(bundled.decimals);
         if (d !== null) return d;
@@ -100,7 +102,7 @@ function explorerSymbol(lower, wallets) {
 // explorer reported: the same sources and the same precedence
 // resolveTokenDecimals() uses, so a token's name and its scale are drawn from
 // the same place and the two can no longer disagree about which sources they
-// trust. `sources` is { trackedTokens, wallets }, shaped as on `state`.
+// trust. `sources` is as for resolveTokenDecimals().
 //
 // A tracked or explorer-reported symbol is attacker-influenced text, so it is
 // held to the spoof rule (symbolSpoof.js): a candidate that wears a bundled or
@@ -111,7 +113,7 @@ function resolveTokenSymbol(tokenAddress, sources) {
     const lower = (tokenAddress || "").toLowerCase();
     if (!lower) return null;
 
-    const bundled = TOKEN_BY_ADDRESS.get(lower);
+    const bundled = bundledToken(lower, sources && sources.chainId);
     if (bundled && bundled.symbol) return bundled.symbol;
 
     const tracked = ((sources && sources.trackedTokens) || []).find(