fix: the swap decoder names where a WRAP_ETH pays and shows a V4 step's ETH as a maximum when the router may hold ETH (closes #665)

A `WRAP_ETH` that sets the input side and pays its WETH to anyone but
the router names that recipient on its `Moved to` line.

V4 pays a `SETTLE` of ETH from the router's own ETH, whichever payer it
names. When an earlier step may leave ETH in the router, the ETH that
the user pays a later V4 step gets lines of its own. Their
`Moved from the sender` line reads `Up to <amount>`, or
`Unknown (could not be decoded)` when the amount is not known. The
decoder never subtracts the router's ETH from that amount. Without such
an earlier step, the lines read as before.

Model: opus-5-5

README.md

@@ -1268,6 +1268,9 @@ see Transaction Decoding), do not always read as a number. They can read:
   wording. When a V2 or V3 exact-out step sets `Min. received`, that line shows
   its `amountOut`, the exact amount it buys. When earlier swap steps also pay
   that token to the user, the line shows the sum (see Transaction Decoding).
+  When the router may hold ETH from an earlier step, the `Moved from the sender`
+  line of ETH that the user pays a V4 step also reads `Up to <amount>` (see
+  Transaction Decoding).
 - `All available (V4 open delta)`: the swap's `Amount` line, when the amount it
   shows is a V4 exact-in `amountIn` of zero. V4 reads that zero as "use the
   whole open delta", so the calldata states no quantity. Transaction Decoding
@@ -3524,23 +3527,26 @@ Currently supported:
   of any amount but `OPEN_DELTA` pays that amount, and a `SETTLE` of
   `OPEN_DELTA` or a `SETTLE_ALL` pays what the step owes, as above. So a V4 step
   that swaps 400 USDT, with a `SETTLE` of 5,000 USDT paid by the user and the
-  rest taken to another address, reads `5000.0000 USDT`. A later step that pays
-  an ERC-20 token from the router takes none of that token from the user's
-  wallet. A V2 exact-in whose `amountIn` is `ALREADY_PAID` takes nothing either.
-  A V4 `SETTLE` of ETH paid from the router still takes from the user's wallet,
-  since the router holds the transaction's value. When the decoder does not know
-  the amount of such a `SETTLE`, as for `CONTRACT_BALANCE`, that `SETTLE` counts
-  as a later step's take. When an earlier step left ETH in the router, that ETH
-  may pay part of a `SETTLE` of ETH paid from the router. That `SETTLE` then
-  gets lines of its own, with `Up to` before its amount. A later take of
-  `Token In` that only the user's wallet pays is added to the total while both
-  are quantities: a V3 exact-in of 600 USDT and a V2 exact-in of 400 USDT, both
-  paid by the user, read `1000.0000 USDT`. When the decoder does not know a
-  take's amount, the total is not known and there is no `Amount` line. A
-  `PERMIT2_PERMIT` names `Token In` only when its amount, `Unlimited` included,
-  stands as the `Amount` figure in place of the total, which it does only in the
-  plain shape of Uniswap's own routes: it comes before the step that sets the
-  input side, it is the only `PERMIT2_PERMIT` in the transaction and there is no
+  rest taken to another address, reads `5000.0000 USDT`. V4 pays a `SETTLE` of
+  ETH from the router's own ETH, whichever payer it names. So when the router
+  may hold ETH from an earlier step (see above), the ETH that the user pays a V4
+  step gets lines of its own (see below). A later step that pays an ERC-20 token
+  from the router takes none of that token from the user's wallet. A V2 exact-in
+  whose `amountIn` is `ALREADY_PAID` takes nothing either. A V4 `SETTLE` of ETH
+  paid from the router still takes from the user's wallet, since the router
+  holds the transaction's value. When the decoder does not know the amount of
+  such a `SETTLE`, as for `CONTRACT_BALANCE`, that `SETTLE` counts as a later
+  step's take. When an earlier step left ETH in the router, that ETH may pay
+  part of a `SETTLE` of ETH paid from the router. That `SETTLE` then gets lines
+  of its own, with `Up to` before its amount. A later take of `Token In` that
+  only the user's wallet pays is added to the total while both are quantities: a
+  V3 exact-in of 600 USDT and a V2 exact-in of 400 USDT, both paid by the user,
+  read `1000.0000 USDT`. When the decoder does not know a take's amount, the
+  total is not known and there is no `Amount` line. A `PERMIT2_PERMIT` names
+  `Token In` only when its amount, `Unlimited` included, stands as the `Amount`
+  figure in place of the total, which it does only in the plain shape of
+  Uniswap's own routes: it comes before the step that sets the input side, it is
+  the only `PERMIT2_PERMIT` in the transaction and there is no
   `PERMIT2_PERMIT_BATCH`, its spender is the router, the router may not let it
   fail, no step before it takes its token, a `PERMIT2_TRANSFER_FROM` of it
   included, or a token the decoder does not know, and the decoder reads every
@@ -3570,34 +3576,39 @@ Currently supported:
   that is not a quantity (a V4 open delta, `ALREADY_PAID`, which keep their
   wording on the `Amount` line, or no stated amount, as of a V4 exact-out step);
   an ETH take whose line reads `Up to` (see above); and one whose amount the
-  decoder does not know. When there is no `Amount` line, each take the total
-  counts gets them too, so that every amount the decoder reads is shown: the
-  amount the step that sets the input side states, when it is a quantity and the
-  user pays that step (a V2 or V3 step whose `payerIsUser` is true, a V4 step
-  the user pays some of its input token, or a `WRAP_ETH`, whose ETH comes from
-  the transaction's value), and each later take of `Token In` added to it. A
-  step that sets the input side gets none when the user pays it none of its
-  input token. A `PERMIT2_PERMIT` the decoder cannot read, then V3 exact-ins of
-  600 USDT and 400 DAI paid by the user, give lines for both amounts. When the
-  step that sets the input side states no amount, the user pays it some of its
-  input token, and there is no `Amount` line, that step gets them too whenever
-  another take's lines give a figure, or a `PERMIT2_TRANSFER_FROM` of its token
-  gives one, on the lines below or, into the router, on its `Paid to` line, so
-  that figure cannot read as all that leaves. When it states no amount and the
-  user pays it none of its input token, that step never gets them, with a permit
-  or without. They come in step order, except that the step that sets the input
-  side comes first when it has them, followed, when there is no `Amount` line,
-  by the other takes the total counts: `Moved from the sender`, its amount,
-  worded as the `Amount` line words one, or `Unknown (could not be decoded)`
-  when the decoder does not know it; `Token moved`, giving the token's address
-  as the `Token In` line does; and `Moved to`, which reads
-  `The swap step that spends it`. A token the decoder does not know gives the
-  `Moved from the sender` line alone. A step may also take from the user's
-  wallet what the decoder did not read: a V4 step whose input or one of whose
-  `SETTLE`s or `SETTLE_ALL`s it cannot read, which the router still runs; a V2
-  or V3 exact-in or exact-out step or a `PERMIT2_TRANSFER_FROM` whose input it
-  cannot read, such as a V3 step whose path is shorter than one token address or
-  has bytes after its last hop; every `PERMIT2_TRANSFER_FROM_BATCH`; every
+  decoder does not know. ETH that the user pays a V4 step when the router may
+  hold ETH gets these three lines too. When there is no `Amount` line, each take
+  the total counts gets them too, so that every amount the decoder reads is
+  shown: the amount the step that sets the input side states, when it is a
+  quantity and the user pays that step (a V2 or V3 step whose `payerIsUser` is
+  true, a V4 step the user pays some of its input token, or a `WRAP_ETH`, whose
+  ETH comes from the transaction's value), and each later take of `Token In`
+  added to it. A step that sets the input side gets none when the user pays it
+  none of its input token. A `PERMIT2_PERMIT` the decoder cannot read, then V3
+  exact-ins of 600 USDT and 400 DAI paid by the user, give lines for both
+  amounts. When the step that sets the input side states no amount, the user
+  pays it some of its input token, and there is no `Amount` line, that step gets
+  them too whenever another take's lines give a figure, or a
+  `PERMIT2_TRANSFER_FROM` of its token gives one, on the lines below or, into
+  the router, on its `Paid to` line, so that figure cannot read as all that
+  leaves. When it states no amount and the user pays it none of its input token,
+  that step never gets them, with a permit or without. They come in step order,
+  except that the step that sets the input side comes first when it has them,
+  followed, when there is no `Amount` line, by the other takes the total counts:
+  `Moved from the sender`, its amount, worded as the `Amount` line words one, or
+  `Unknown (could not be decoded)` when the decoder does not know it;
+  `Token moved`, giving the token's address as the `Token In` line does; and
+  `Moved to`, which reads `The swap step that spends it`. For ETH that the user
+  pays a V4 step when the router may hold ETH, `Moved from the sender` reads
+  `Up to <amount>` for a known amount. For a `WRAP_ETH` that pays its WETH to
+  anyone but the router, `Moved to` names that recipient instead: `The sender`
+  for `address(1)`, and otherwise the address. A token the decoder does not know
+  gives the `Moved from the sender` line alone. A step may also take from the
+  user's wallet what the decoder did not read: a V4 step whose input or one of
+  whose `SETTLE`s or `SETTLE_ALL`s it cannot read, which the router still runs;
+  a V2 or V3 exact-in or exact-out step or a `PERMIT2_TRANSFER_FROM` whose input
+  it cannot read, such as a V3 step whose path is shorter than one token address
+  or has bytes after its last hop; every `PERMIT2_TRANSFER_FROM_BATCH`; every
   `EXECUTE_SUB_PLAN`, wherever it stands; and every step it fails on. Each such
   step gives one `Moved from the sender` line among those, reading
   `Unknown (could not be decoded)`. That line, or any line for a token the