chore: remove dead exports and share copied view helpers (closes #168)

AddressDetail and AddressToken defined their own isoDate() and
timeAgo(), hiding the shared pair in helpers.js, so a fix there would
not have reached them. The copies were identical and are deleted;
blockieHtml() and tokenLabel(), each defined twice, move to helpers.js.
A new test shows the history rows and the transaction detail view
write the time with the shared pair.

Deleted as never called: explorerLink(), ETHEREUM_SEPOLIA_CHAIN_ID,
getWalletValue() and getTotalValue() with their tests. Home's "Total:"
is the active address's total, as README.md already says.
addressColor() and etherscanAddressUrl() are no longer exported.

Model: opus-5-5

src/popup/views/txStatus.js

@@ -13,8 +13,8 @@ const {
     explorerUrl,
     displaySymbol,
     clearViewStack,
+    tokenLabel,
 } = require("./helpers");
-const { resolveTokenSymbol } = require("../../shared/approvalAmount");
 const { state } = require("../../shared/state");
 const { nativeCurrencyByChainId } = require("../../shared/networks");
 const { getProvider } = require("../../shared/balances");
@@ -243,17 +243,6 @@ function showSuccess(txInfo, txHash, blockNumber) {
     ctx.doRefreshAndRender();
 }
 
-// The symbol shown for a decoded token line, resolved from the bundled list,
-// the tokens the user tracks, and the explorer's report — the same chain the
-// approval screen uses. Null when no source names one, so the line keeps
-// saying `Unknown token`.
-function tokenLabel(address) {
-    return resolveTokenSymbol(address, {
-        trackedTokens: state.trackedTokens,
-        wallets: state.wallets,
-    });
-}
-
 function decodedDetailsHtml(decoded) {
     if (!decoded || !decoded.details) return "";
     let html = `<div class="border border-border border-dashed p-2 mb-3">`;