fix: the balance list and the add-token screens apply the spoof rule to tracked tokens (closes #705)

The balance list gave a tracked token a zero row while "Show tracked
tokens with zero balance" was on, even when the spoof rule refuses the
token. balanceLinesForAddress() now asks isSpoofedSymbol() before it adds
that row.

AddToken and SettingsAddToken now refuse such a token after the contract
lookup, with a flash message that says why. The bundled-list buttons on
SettingsAddToken need no check, because the rule never refuses a bundled
token.

The README and docs/README.md now say that the balance list drops such a
token whatever the settings.

Model: opus-5-5

docs/README.md

@@ -380,10 +380,8 @@ but comes from an unrecognized contract, it is identified as a spoof and hidden.
 In your transaction history this is the "Hide fake tokens impersonating a known
 symbol" setting, which you can switch off; doing so also stops new entries being
 added to the fraud contract blocklist below, since detecting a spoof is what
-fills it. The send token list always applies the check. Your balances apply it
-too, with one exception: a token claiming the symbol "ETH" is not filtered
-there, so a fake "ETH" token can still show up in your balance list even though
-it is hidden from your transaction history and from the send token list.
+fills it. The send token list always applies the check. Your balance list always
+applies the check too.
 
 **Low-holder token filtering.** Tokens with fewer than 1,000 holders are hidden
 from transaction history and the send token list, and are left out of your