amount %amt @@ -%amt is not allowed when %amt is negative; CSV import

[PSLLSP]

$ hledger --version
hledger 1.32.3, linux-x86_64

@@ cannot parse negative amounts (@@ -%amt results in @@ --123.45 and that is a problem for a parser)

Error:

$ hledger -f demo-eur.csv print
hledger: Error: error: could not parse "--2 345.56 USD @@ --2 456.78 EUR" as an amount
CSV record: "2023-01-25","test3","-2 345.56","USD","-2 456.78","EUR"
the account3 rule is: equity:conversion
the account2 rule is: assets:cash
the amount2 rule is: -%3 %4 @@ -%5 %6
the account1 rule is: expenses:assorted
the amount1 rule is: %3 %4 @@ %5 %6
the amount rule is: %5 %6
the comment rule is: \n%1,%2,%3,%4,%5,%6
the date rule is: %1
the description rule is: DEMO|%2

the parse error is:      1:14:
  |
1 | 2 345.56 USD @@ --2 456.78 EUR
  |              ^
unexpected '@'
expecting end of input, ledger-style lot cost, ledger-style lot date, ledger-style lot note, or valuation expression

you may need to change your amount*, balance*, or currency* rules, or add or change your skip rule

CSV file to replicate the bug. The first 2 lines are imported without issue but third line is troublemaker because it has negative numbers:

$ cat demo-eur.csv
2023-01-23,test1,1 234.56,EUR,1 234.56,EUR
2023-01-24,test2,2 345.56,USD,2 456.78,EUR
2023-01-25,test3,-2 345.56,USD,-2 456.78,EUR
2023-01-26,test4,+2 345.56,USD,+2 456.78,EUR

CSV rules import file:

$ cat demo-eur.csv.rules 
# hledger import rules, test

date  %1
description DEMO|%2

amount %5 %6
#amount %6 %5    # to test other issue (-123 -> EUR --123)

amount1 %3 %4 @@ %5 %6
amount2 -%3 %4 @@ -%5 %6
#amount2 %4 -%3 @@ %6 -%5  # similar issue (-123 EUR -> EUR --123)

account1 expenses:assorted
account2 assets:cash
account3 equity:conversion

# debug
comment \n%1,%2,%3,%4,%5,%6

Even positive numbers could be troublemakers:

$ grep "test4" demo-eur.csv
2023-01-26,test4,+2 345.56,USD,+2 456.78,EUR