[sarankumar1325]

Fixes #15697

apply_modifiers stripped the leading zeros of the 9-digit %N value before truncating it to the requested width. As a result, %3N printed 512 for 0.005123456 (GNU prints 005), and consecutive %s%3N timestamps could go backwards.

%N is a fraction, not an integer, so it now goes through its own small helper:

• a width keeps the first width digits, leading zeros included;
• a wider width pads on the right (%12N gives 005123456000, not 000005123456);
• inside that width, trailing zeros become the pad character (%_3N of .050 gives 05 ), and the - flag drops them (%-3N gives 05);
• with no width, %N, %-N and %+N stay 9 digits, and %_N space-pads the trailing zeros as before.

The two %N-only branches left in the generic padding path could no longer be reached, so I removed them.

Testing

• I compared uutils against GNU date 9.7 on 24 flag/width combinations (%N %3N %_3N %-3N %_N %-N %12N %_12N %03N %+3N %^3N %1N %-9N %-12N %_-3N %-_3N %_03N %0_3N %+N %+12N %_+3N %0N %_9N %9N), each at @0.005123456, @0.123, @0 and @0.05. All outputs match. Before this change, 13 of them differed.
• New test test_date_strftime_n_width_keeps_leading_zeros in tests/by-util/test_date.rs. It fails on main and passes with this change.
• cargo test --features date --no-default-features -- test_date (193 passed), cargo test -p uu_date (42 passed), and cargo clippy --all-targets -- -D warnings for the date feature are all clean.

I used an AI assistant to help write this change. I reviewed every line, and I worked out the expected outputs by running GNU date as a black box, not from its source.

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[cakebaker]

Thanks for your PR!