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/confirmTx.js

@@ -13,6 +13,7 @@ const {
     displaySymbol,
     nativeCurrency,
     renderAddressHtml,
+    blockieHtml,
     attachCopyHandlers,
     goBack,
     onViewLeave,
@@ -47,7 +48,6 @@ const {
     validateTransfer,
 } = require("../../shared/txValidation");
 const { log } = require("../../shared/log");
-const makeBlockie = require("ethereum-blockies-base64");
 const txStatus = require("./txStatus");
 
 let pendingTx = null;
@@ -67,11 +67,6 @@ function restore() {
     }
 }
 
-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">`;
-}
-
 function confirmAddressHtml(address, ensName, title) {
     const blockie = blockieHtml(address);
     return (