fix: prefer suffixed locales to avoid Perl 5.42.0 panic (GH #448)

[toddr-bot]

What

Prefer suffixed locale names (e.g. en_GB.UTF-8) over bare names (e.g. en_GB) when probing locale availability in Template::Plugin::Date.

Why

Perl 5.42.0 introduced a fatal panic in locale.c when nl_langinfo(CODESET) returns empty for a locale that setlocale() accepted. On macOS, bare locale names like en_GB lack a codeset, so setlocale(LC_ALL, "en_GB") succeeds but subsequent strftime() panics because Perl internally queries the codeset.

Reproducer (no Template modules needed):

perl -MPOSIX -e 'setlocale(LC_ALL, "en_GB") and print strftime("%A", localtime)'

See #448 for full analysis.

How

Two changes to the locale probe loop in Date.pm:

1. Try suffixed locales first, bare last: for my $suffix (@LOCALE_SUFFIX, '') instead of ('', @LOCALE_SUFFIX). On macOS, en_GB.UTF-8 matches before the bare en_GB, avoiding the panic.

2. Reorder @LOCALE_SUFFIX: .UTF-8 moved to front since it's the most common modern encoding. Previous order was .ISO8859-1 first (historical).

Both changes are backwards compatible — if only bare locale names exist on a system, the fallback at the end of the loop still finds them.

The mirror loop in t/date.t is updated to match.

Testing

• t/date.t passes
• Full test suite passes (make test)
• The actual panic requires Perl 5.42.0 + macOS to reproduce

Closes #448

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Quality Report

Changes: 2 files changed, 3 insertions(+), 3 deletions(-)

Code scan: clean

Tests: passed (OK)

Branch hygiene: clean

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