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 TOKEN_BY_ADDRESS 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.

isSpoofedSymbol() takes the chain id of the token's network. It checks the
bundled list's symbols only on Ethereum Mainnet. The native asset's labels
stay reserved on every network.

Eighteen existing tests and three shared test helpers read the bundled
list without naming a network. Each now names Ethereum Mainnet.

Model: opus-5-5

tests/approvalAmount.test.js

@@ -90,9 +90,11 @@ beforeEach(() => {
 });
 
 describe("resolveTokenDecimals", () => {
+    // The bundled list is read only for a token on Ethereum Mainnet.
     test("prefers the bundled list", () => {
         state.trackedTokens = [{ address: USDC, symbol: "USDC", decimals: 2 }];
-        expect(resolveTokenDecimals(USDC, state)).toBe(6);
+        const sources = { chainId: "0x1", trackedTokens: state.trackedTokens };
+        expect(resolveTokenDecimals(USDC, sources)).toBe(6);
     });
 
     test("reads a token the user tracks", () => {
@@ -124,7 +126,8 @@ describe("resolveTokenDecimals", () => {
     // answers 0 is used rather than fallen past like the unusable entry above.
     test("uses a bundled scale of zero", () => {
         state.trackedTokens = [{ address: SLP, symbol: "SLP", decimals: 18 }];
-        expect(resolveTokenDecimals(SLP, state)).toBe(0);
+        const sources = { chainId: "0x1", trackedTokens: state.trackedTokens };
+        expect(resolveTokenDecimals(SLP, sources)).toBe(0);
     });
 
     test("uses a tracked scale of zero", () => {