fix: judge the symbol a user sees, not the bytes a contract returns (closes #260)

A token whose symbol is " ETH " missed KNOWN_SYMBOLS on all three surfaces
while HTML collapsed the padding and painted it as ETH next to the user's
real ETH. isSpoofedSymbol() now normalizes before the lookup: NFKC, every
Unicode format character removed wherever it sits, then trimmed, then
uppercased. All three surfaces inherit it unchanged.

Covered: ASCII and Unicode whitespace padding, zero-width and other
invisible format characters, and compatibility variants such as fullwidth
letters. Knowingly left open, and asserted as open in the suite: confusables
that are distinct letters (Cyrillic capital Ie), bidi reordering, and
interior whitespace, which renders differently and so is not the confusion.

No symbol in KNOWN_SYMBOLS or the bundled token list contains whitespace or
a non-ASCII character, so nothing legitimate is newly filtered; a test walks
the whole table and asserts it.

The balance list's token-type gate is now case-insensitive. It compared
exactly, so an explorer writing "erc-20" would silently drop a real holding
before any filter ran. Which types are admitted is unchanged.

TODO.md

@@ -44,6 +44,17 @@ undefined identifiers, which is how
 
 # Completed Steps
 
+- 2026-08-12: The known-symbol spoof rule now judges the symbol a user actually
+  sees. `isSpoofedSymbol()` normalizes before the lookup — NFKC, then every
+  Unicode format character removed, then trimmed — so `" ETH "`, a no-break
+  space, a zero-width space and a fullwidth `ＥＴＨ` are all caught on the
+  balance list, the history and the send selector at once. Confusables that are
+  distinct letters (Cyrillic `Е`) and bidi reordering stay knowingly open and
+  are asserted as open in the suite. No bundled symbol contains whitespace or a
+  non-ASCII character, so nothing legitimate is newly filtered; the balance
+  list's token-type gate also became case-insensitive, which no longer drops a
+  real holding if an explorer writes `erc-20`
+  ([#260](https://git.eeqj.de/sneak/AutistMask/issues/260)).
 - 2026-08-12: The transaction confirmation screen has browser coverage. The
   end-to-end suite reaches ConfirmTx for both the native ETH and the ERC-20 path
   off a funded-balance fixture, and asserts the pending, funded, over-balance