Reject overflowing digit recompositions

[krotname]

Motivation

• Restore previous semantics where concatenated digit sequences reject out-of-range results instead of silently wrapping due to unchecked int arithmetic.

Description

• Change DescendingOrder.sortDesc to build the reordered digits with a StringBuilder and return Integer.parseInt(...) so values outside int range throw NumberFormatException.
• Change MinimumLine.minValue to concatenate sorted distinct values via mapToObj(String::valueOf) and Collectors.joining() and return Integer.parseInt(...) to preserve concatenation semantics and reject overflow.
• Add regression tests rejectsReorderedValuesOutsideIntegerRange in DescendingOrderTest and rejectsConcatenatedValuesOutsideIntegerRange in MinimumLineTest that assert a NumberFormatException is thrown for the reported overflowing inputs.

Testing

• Ran mvn -q -Dtest=DescendingOrderTest,MinimumLineTest test and the targeted tests passed.
• Ran full test suite with mvn -q test and it completed successfully in this environment.
• Ran git diff --check to validate no whitespace/diff issues and the working tree was clean.

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Codex Task

[krotname]

Закрываю как superseded by #116: изменения перенесены в одну проверенную ветку, все review findings учтены; локальный mvn verify прошёл полностью.