refactor(php-shim): use std::path::MAIN_SEPARATOR over a shim constant

The shim's DIRECTORY_SEPARATOR was hardcoded to "/", so every ported
`'\\' === DIRECTORY_SEPARATOR` check compared against a constant that
does not track the target platform. std::path::MAIN_SEPARATOR and
MAIN_SEPARATOR_STR carry the same meaning as PHP's constant and resolve
per platform, so the Windows branches are selected on Windows targets.

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

3 files changed, 4 insertions, 5 deletions

diff --git a/crates/shirabe-external-packages/src/symfony/console/helper/question_helper.rs b/crates/shirabe-external-packages/src/symfony/console/helper/question_helper.rs
index 2091225d..f5242d9a 100644
--- a/crates/shirabe-external-packages/src/symfony/console/helper/question_helper.rs
+++ b/crates/shirabe-external-packages/src/symfony/console/helper/question_helper.rs
@@ -685,7 +685,7 @@ impl QuestionHelper {
         input_stream: &shirabe_php_shim::PhpResource,
         trimmable: bool,
     ) -> anyhow::Result<Result<String, RuntimeException>> {
-        if shirabe_php_shim::DIRECTORY_SEPARATOR == "\\" {
+        if std::path::MAIN_SEPARATOR == '\\' {
             let mut exe = format!(
                 "{}/../Resources/bin/hiddeninput.exe",
                 shirabe_php_shim::dir()
diff --git a/crates/shirabe-external-packages/src/symfony/console/output/stream_output.rs b/crates/shirabe-external-packages/src/symfony/console/output/stream_output.rs
index 9140dbc8..8ee2f186 100644
--- a/crates/shirabe-external-packages/src/symfony/console/output/stream_output.rs
+++ b/crates/shirabe-external-packages/src/symfony/console/output/stream_output.rs
@@ -98,8 +98,7 @@ impl StreamOutput {
             return false;
         }
 
-        if "\\" == shirabe_php_shim::DIRECTORY_SEPARATOR
-            && shirabe_php_shim::sapi_windows_vt100_support(stream)
+        if std::path::MAIN_SEPARATOR == '\\' && shirabe_php_shim::sapi_windows_vt100_support(stream)
         {
             return true;
         }
diff --git a/crates/shirabe-external-packages/src/symfony/console/terminal.rs b/crates/shirabe-external-packages/src/symfony/console/terminal.rs
index 7fca27e8..353dffcb 100644
--- a/crates/shirabe-external-packages/src/symfony/console/terminal.rs
+++ b/crates/shirabe-external-packages/src/symfony/console/terminal.rs
@@ -69,7 +69,7 @@ impl Terminal {
 
         let result = shirabe_php_shim::shell_exec(&format!(
             "stty 2> {}",
-            if shirabe_php_shim::DIRECTORY_SEPARATOR == "\\" {
+            if std::path::MAIN_SEPARATOR == '\\' {
                 "NUL"
             } else {
                 "/dev/null"
@@ -81,7 +81,7 @@ impl Terminal {
     }
 
     fn init_dimensions() {
-        if shirabe_php_shim::DIRECTORY_SEPARATOR == "\\" {
+        if std::path::MAIN_SEPARATOR == '\\' {
             let ansicon = shirabe_php_shim::getenv("ANSICON");
             let mut matches: Vec<Option<String>> = Vec::new();
             if let Some(ansicon) = &ansicon