feat(php-shim): render human-facing timestamps in the local timezone

Split date() into date_utc() and date_local(), the latter resolving the
system's local timezone through the tzfile crate ($TZ, then
/etc/localtime, falling back to UTC when neither is readable). The
timestamps Composer renders for humans -- the GitHub OAuth token note,
the GitHub API rate limit reset time, the Perforce client spec fields and
the "today" check of the show command -- now go through date_local().

PHP resolves its default timezone from the date.timezone ini setting,
which Shirabe does not read, so date_default_timezone_get/set have no
input left to model and are dropped from the shim and its callers. The
resulting difference is recorded in docs/known-incompatibilities.md.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

1 files changed, 3 insertions, 3 deletions

diff --git a/crates/shirabe/src/command/show_command.rs b/crates/shirabe/src/command/show_command.rs
index e5d5a1f2..f2246cbe 100644
--- a/crates/shirabe/src/command/show_command.rs
+++ b/crates/shirabe/src/command/show_command.rs
@@ -39,8 +39,8 @@ use indexmap::IndexMap;
 use shirabe_pcre::{CaptureKey, Preg};
 use shirabe_php_shim::{
     CmpOp, DATE_ATOM, InvalidArgumentException, LogicException, PhpMixed, UnexpectedValueException,
-    array_search, date, date_format_to_strftime, extension_loaded, impl_php_class, in_array_loose,
-    in_array_strict, php_regex, realpath, strtolower, version_compare,
+    array_search, date_format_to_strftime, date_local, extension_loaded, impl_php_class,
+    in_array_loose, in_array_strict, php_regex, realpath, strtolower, version_compare,
 };
 use shirabe_semver::Semver;
 use shirabe_semver::constraint::AnyConstraint;
@@ -1484,7 +1484,7 @@ impl ShowCommand {
         if release_date
             .format(date_format_to_strftime("Ymd"))
             .to_string()
-            == date("Ymd", None)
+            == date_local("Ymd", None)
         {
             return "today".to_string();
         }