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/helpers.js

@@ -13,10 +13,12 @@
 // reasoning behind it are; it is re-exported below so views keep importing
 // it from here.
 const { formatEther } = require("ethers");
+const makeBlockie = require("ethereum-blockies-base64");
 const {
     truncateAmountNeverZero,
     isBelowOneMillionth,
 } = require("../../shared/amountDisplay");
+const { resolveTokenSymbol } = require("../../shared/approvalAmount");
 const { DEBUG } = require("../../shared/constants");
 const { escapeHtml } = require("../../shared/html");
 const { isDebug } = require("../../shared/log");
@@ -278,6 +280,17 @@ function nativeCurrency() {
     return currentNetwork().nativeCurrency;
 }
 
+// The symbol shown for a token line, resolved from the bundled list, the
+// tokens the user tracks, and the explorer's report — the same chain the
+// amount line's scale comes from. Null when no source names one, so the token
+// lines keep saying `Unknown token` for a token nothing knows.
+function tokenLabel(address) {
+    return resolveTokenSymbol(address, {
+        trackedTokens: state.trackedTokens,
+        wallets: state.wallets,
+    });
+}
+
 // A network fee in wei as the confirmation and approval screens both show it:
 // the ETH figure through truncateAmountNeverZero() and labelled `symbol`, the
 // native currency of the network the fee is paid on, then its USD value when
@@ -446,6 +459,11 @@ function addressDotHtml(address) {
     return `<span style="width:8px;height:8px;border-radius:50%;display:inline-block;background:${color};margin-right:4px;vertical-align:middle;flex-shrink:0;"></span>`;
 }
 
+function blockieHtml(address) {
+    const src = makeBlockie(address);
+    return `<img src="${escapeHtml(src)}" width="48" height="48" style="image-rendering:pixelated;border-radius:50%;display:inline-block">`;
+}
+
 // Look up an address across all wallets and return its title
 // (e.g. "Address 1.2") or null if it's not one of ours.
 function addressTitle(address, wallets) {
@@ -492,6 +510,9 @@ function formatAddressHtml(address, ensName, maxLen, title) {
     return renderAddressHtml(address, { title, ensName, maxLen });
 }
 
+// A transaction's time as every screen shows it (README, Display
+// Consistency): the ISO datetime, in UTC when the UTC Timestamps setting is
+// on, and the relative age. Views import these two; they keep no copies.
 function isoDate(timestamp) {
     const d = new Date(timestamp * 1000);
     const pad = (n) => String(n).padStart(2, "0");
@@ -691,9 +712,10 @@ module.exports = {
     addressHoldsFunds,
     unknownableAmount,
     nativeCurrency,
+    tokenLabel,
     formatFee,
-    addressColor,
     addressDotHtml,
+    blockieHtml,
     escapeHtml,
     displaySymbol,
     addressTitle,
@@ -703,7 +725,6 @@ module.exports = {
     renderAddressHtml,
     copyableHtml,
     attachCopyHandlers,
-    etherscanAddressUrl,
     etherscanLinkHtml,
     explorerUrl,
     EXT_ICON,