fix: a Permit2 transfer of the zero address never reads as ETH (closes #685)

Permit2 moves no ETH, but the swap decoder read the zero address in a
PERMIT2_TRANSFER_FROM as ETH, with an ETH figure. Such a move now names
the zero address as its token and gives its amount in base units, on its
Moved from the sender line or, into the router, on its Paid to line.

The zero-address check the permit lines already made is now one function,
permit2TokenInfo(), which the move lines share. tokenMovedLine() takes
the token's info instead of its address.

A V4 step of ETH that states no amount still gets its own lines beside
such a move. A test covers that case.

Model: opus-5-5

README.md

@@ -3564,10 +3564,14 @@ Currently supported:
   on every router but `UniversalRouterV1`, and otherwise gives the address. A
   move into the router needs none of them, because its `Paid to` line and
   `Token moved into the router` line already give the amount, the token and
-  where it goes, and so its amount is shown once. Every `PERMIT2_PERMIT` whose
-  amount does not stand as the `Amount` figure, before the step that sets the
-  input side or after it, gives three lines, in step order, after those for each
-  `PERMIT2_TRANSFER_FROM`: `Permit2 allowance`, its amount, for example
+  where it goes, and so its amount is shown once. For a move of the zero
+  address, `Moved from the sender` gives the amount in base units and
+  `Token moved` gives the zero address. For such a move into the router, the
+  `Paid to` line gives the amount in base units and
+  `Token moved into the router` gives the zero address. Every `PERMIT2_PERMIT`
+  whose amount does not stand as the `Amount` figure, before the step that sets
+  the input side or after it, gives three lines, in step order, after those for
+  each `PERMIT2_TRANSFER_FROM`: `Permit2 allowance`, its amount, for example
   `5000.0000 DAI`, or `Unlimited` for Permit2's maximum; `Allowance token`,
   giving the token's address as the `Token In` line does; and
   `Allowance spender`, the address it lets take the token. Only a permit whose