fix: history rows show the ISO datetime and the age (closes #760)

Home, AddressDetail and AddressToken showed only the relative age, with
the datetime as a tooltip. Each row now shows the datetime and then the
age in parentheses, on a line of its own, through transactionTimeHtml()
in helpers.js, which TransactionDetail also uses. The direction label
moves to its own right-aligned line below.

Model: opus-5-5

README.md

@@ -1274,9 +1274,8 @@ A native amount is labelled with the native currency of the transaction's chain:
 `src/shared/networks.js`). The balance lists and Send use the active network's.
 The decoded swap lines call the native currency `ETH` on both networks.
 
-TransactionDetail shows the time as an ISO datetime and a relative age. A
-history row shows the age, with the datetime as its tooltip. With "UTC
-Timestamps" on, the datetime is in UTC.
+TransactionDetail and every history row show the time as an ISO datetime and
+then a relative age. With "UTC Timestamps" on, the datetime is in UTC.
 
 Every nonzero holding is stored exactly. A token holding below 0.000001 is left
 out of: