fix: an address holding only unpriced tokens is no longer totalled at $0.00 (closes #261)

Prices are fetched for the top 25 tokens only, so an address can hold real
assets this build has no price for. The address total summed the priced
holdings and printed the result as the total, so an address holding nothing
but unpriced ERC-20s was reported as worth $0.00 — wrong in the direction
that matters, and on the address-removal confirmation it sat directly under
"This address holds a balance."

getAddressValue() returns { usd, partial }: the value of the priced holdings,
and whether an unpriced holding was left out of it. Worth zero and worth an
unknown amount stay separate facts, as an absent holders_count stays separate
from a count of zero. formatAddressTotal() is the one rendering of that pair,
so no screen can word it differently:

  - nothing knowable (testnet, before the first fetch): no total line
  - everything priced:  "Total: $5,500.00"
  - part priced:        "Total: $3,000.00 plus unpriced tokens"
  - nothing priced:     "Total: unpriced tokens only"

A partial total is kept rather than suppressed: the figure is the ETH and
priced tokens the user does hold and is correct as far as it goes, so it is
named as a floor instead of being thrown away. What is never printed is a
figure covering no holdings at all.

All four call sites read it — the Home summary line, the Home wallet list,
AddressDetail and the removal confirmation — and getWalletValue() and
getTotalValue() carry partial up so a future consumer cannot lose it.
The per-token balance lines are unchanged: a token with no price shows its
quantity and a blank USD column.

tests/addressValue.test.js covers the only-unpriced, genuinely-zero and
fully-priced cases at the helper, at its formatter, and through both call
sites that return their markup as a string. Written first and watched fail
on the unfixed helper: the Home wallet list gave "$0.00" and the removal
confirmation "Total: $0.00" for an address holding 5000 unpriced tokens.

TODO.md

@@ -45,6 +45,22 @@ undefined identifiers, which is how
 
 # Completed Steps
 
+- 2026-08-17: An address total no longer reports `$0.00` for holdings it cannot
+  price. Prices exist for the top 25 tokens only, so the priced-only sum was
+  printed as the total and an address holding nothing but unpriced ERC-20s was
+  shown as worth nothing — directly under "This address holds a balance." on the
+  address-removal confirmation. `getAddressValue()` in `src/shared/prices.js`
+  now returns `{ usd, partial }`, keeping worth-zero and worth-an-unknown-amount
+  apart the way an absent `holders_count` is kept apart from a count of zero,
+  and every screen renders it through the one `formatAddressTotal()`: the figure
+  when it covers everything, the figure marked `plus unpriced tokens` when it
+  covers part, and `Total: unpriced tokens only` when it would cover nothing.
+  Home, AddressDetail and the removal confirmation all read it, and
+  `getWalletValue()`/`getTotalValue()` carry `partial` up. Covered by
+  `tests/addressValue.test.js` — the only-unpriced, genuinely-zero and
+  fully-priced cases at the helper and at both call sites that return their
+  markup — demonstrated failing first
+  ([#261](https://git.eeqj.de/sneak/AutistMask/issues/261)).
 - 2026-08-17: `README.md` no longer advertises a defect the wallet does not
   have. The End-to-End Tests section listed the EIP-1193 code being dropped in
   the last hop into the page as a standing limit of the dApp coverage; that